marvelous thank you okay everyone so um it's great to see so many of you here today my name's georgia mason i'm director of the campbell center for the study of animal welfare thanks so much for being here thanks very much to our speaker it's wonderful to see you all and i'd also like to acknowledge with gratitude that the campbell center and the university of guelph reside on the treaty lands and territory of the mississaugas of the credit first nation um the land was first purchased from this nation by the british in 1784 in a deal that um history tells us was probably shady so um grateful respect and acknowledgement there um it's also wonderful to welcome steph tory um who for a very long time has been an active really valuable member of the group here and indeed she's still an adjunct faculty member in animal bio sciences um dr torrey is an expert on poultry and swine welfare she's authored and co-authored over 60 peer-reviewed publications and her work and expertise has informed policy and auditing schemes around farm animal welfare genetics and transportation and euthanasia and she's currently a research scientist with tround nutrition leading a global team that's validating nutritional products poultry production health and welfare and she was just telling us earlier how this means some um because her team is really all over the world she's often having meetings at 5 30 in the morning just to make things work um i'm part of the team i'm not i'm not leading the team i'm i'm a member of the team okay all right sorry i that's okay okay i'm sure you will be okay so steph is american she's a native of massachusetts she did her phd here in guelph she was then a research scientist with um agriculture in agri-food canada first based in quebec then seconded back here in ontario and then she became a research associate um at the in the campbell center on the um huge grant and the huge project she's going to talk to us about today so her topic's really important because globally 70 million broiler or meat chickens are raised each year so that's pretty much 10 times the number of humans on the planet and more than 90 percent of them grow at a phenomenal rate they meet reach market weight at just six weeks or so when they're really babies so is this accelerated growth a problem so in this seminar steph's going to tackle this topic and discuss the welfare of broiler chickens and whether a transition to a slower growing genetic stock would have a measurable effect on their welfare thanks so much there great thanks for that introduction georgia um it's great to see a number of um familiar names in the in the participant list and and some new names and i hope that we can have some good discussions at the end of this if you have any additional questions my email address is here as georgia said i'm at trial nutrition in post lunch as part of the global validation team okay so while i'm the only one presenting today it was really the scientists that did the work for this study uh we're really fortunate to have an amazing team of people um including dr lauren dawson um the now dr miriam nacemento dos santos dr mohammadi gayster daniel rothschild jen jen liu and not pictured our doctor um either arizola and lucas silly so the chicken that you find in the grocery store or at um or at the restaurants and such um is incredibly homogeneous so all the breasts are the same large size you go and buy a package of breasts to cook and they'll all be approximately the same size um all the go to kfc and all the fried chicken pieces will be about the same size and that's because 90 of the chicken that's available at the grocery stores and in restaurants is from a conventional broiler chicken which is a white rock and cornish and broiler chickens have changed really significantly over the last six years with most of those changes coming in the last 40 or so years in the early 1980s tyson foods realized that breasts were worth more than other parts of the chicken and so they called for more meat and less bones on chickens and indeed in canada breasts are about 1.75 times that of thigh meat so breeding companies certainly heated the call and started breeding for greater breast guilt and you can see from this picture um by martin swedoff that it's been quite a dramatic change in the confirmation of broiler chickens due to genetics now along with larger breasts boiler chickens are growing faster than ever before so broiler chickens reach about 2.1 kilograms so a light market weight in about five weeks now whereas some 45 years ago it took twice that amount of time however in particular in north america chickens are being marketed at heavier body weights than that 2.1 kilogram chickens are sold predominantly for processed parts um so they're grown to an older age about six or seven weeks and up to about four kilograms of body weight and so while nutrition veterinary medicine management housing have all had some influence on that growth rate most of the changes in production have come from genetic selection but what does that mean for the bird so brother chickens are highly productive but it comes at a cost to their welfare and this table summarizes the results of five large epidemiological studies on predominantly on physical parameters including things like mortality footpad dermatitis hawk burns and lameness and so across these studies they found mortality to be about on par with industry so around three three and a half percent which is generally the industry standard um and the prevalence of moderate to severe foot pad lesions fpd here ranged anywhere from one and a half to 50 percent of the flocks of the birds and moderate to severe lameness range from 15 to about 35 percent now we know from published research that severe for pad lesions and severe lameness are painful for boiler chickens so while things have have vastly improved over the last 20 to 30 years due to genetic companies incorporating some of these welfare traits into their selection schemes there's still room for significant improvement so that brings me to the question at hand on whether slower growth means better welfare but what exactly is a slow growing broiler um really it depends on who you ask conventional broiler strains the ones i mentioned earlier will grow about gain about 60 to 65 grams per day which means they reach that 2.1 kilograms in about 35 days different countries have different labeling schemes that define what they feel a slow brother is so in france the la belle rouge program stipulates that that brothers have to be in production for at least 81 days so that gives them a growth rate of 26 grams per day rspca in the uk does not include any specific age or weight limit per se but they do have to approve specific slow growing breeds for inclusion within their program for use of the german tier ships label brothers have to grow slower than 45 grams per day and the the dutch better 11 stipulates that they have to grow slower than 38 grams per day and so um really there is quite a bit of variation around around the world mostly requirements for slow growing broilers from europe however global animal partnership or gap whose assurance program a number of food service companies and retailers have signed on to had originally limited their growth rate to 50 grams per day which would get about a 2.1 kilogram bird in about 42 days but in around 2016 they walked that back because they felt like there wasn't enough research to have a hard cut off in terms of growth rates um so they approached me and tina wadowski about doing this large research project to see if growth rate was indeed the driving factor in broader welfare but in order to compare broiler welfare we have to have ways to measure it and so i particularly like the framework described by by david frazier as those three circles for a starting point in looking at welfare so for boilers we would ask if they're healthy and disease-free and growing are they experiencing negative affective states such as pain discomfort hunger thirst frustration or possibly experiencing positive states like pleasure and are they able to perform make motivated behavior over the last five years has been myriad studies um on anywhere from two to four strains of broiler chickens in various environments and pretty much all of these studies the slower growing strains had better welfare outcomes than the conventional strains but there were often other factors at play including free range use or differences in stocking density between the variable within the various studies so in 2017 we started this this project to benchmark data on the welfare of brother chickens taking into account their their behavior their health production physiology and anatomy and carcass and meat quality and we controlled for things like housing feed final ages and weights stocking density hatch conditions and enrichment i will acknowledge that while we controlled for those that means that some of those conditions were not the ideal for particular strains for example we fed all of the strains in our in our study the same diet formulated for slower growth which isn't the ideal diet for for some of the strains in our study we used three conventional vascular strains these strains had a growth estimated growth rate of 60 to 65 grams per day and then we used 13 slower growing strains and 12 of these strains had estimated growth rates from 43 to 55 grams per day and we also had one mixed breed dual purpose group made up of heritage strains and they grew at about 20 grams per day and these the strains are all housed in pens that were segregated by strain within one large room and we aim to have four four pens per strain per trial and house each of the streams in three trials over time we ran eight trials over the course of the two years here i have all the streams that we that we studied by their growth rate on the y-axis here um and these were there this was their growth rate to a heavy body weight we have the conventional strains on the left and the slower growing strains on the right now for two of the strings strains a and strain t we did not have large enough sample size for inclusion of those strains within our statistical analyses so we didn't categorize them for comparisons however since um science has shown us that a lot of the welfare problems co-vary with growth rate we wanted to see if strains of similar growth rates or those with vastly different growth rates had similar or different welfare and so we categorized the strains by their growth rates so that we could compare both the categories of strains and strains within categories so we had two that were within the conventional category and then we divided the remaining 12 strains into three separate categories depending on their growth rate to the heavy body weight like i said the study ran over a two year period and that was to accommodate just the large number of strains and to accommodate each strain being in the study at a couple of different time frames and we collaborated with breeding companies for them to ship us the fertile eggs we did this so that we could account for differences in incubation and hatch conditions and eliminate the transportation and handling major handling on the day patch and so all of the strains were housed in the same environmentally controlled room over time of course they didn't have any outdoor access each pen had the same features so there's a raised platform in the back here um a mineral peck stone a bird is actually sitting on it over on the left and so that was to enable them to be able to perform different behaviors and each pen had an equal amount of males and females which enabled us to account for sex differences and so i said like i said all the birds were hatched vaccinated managed the same in this environmentally controlled room now all the strains were fed the same all vegetable antibiotic-free diet the birds were vaccinated at hatch so that we could use that antibiotic-free diet once the birds reached a the pre-established market weight that i'll i'll talk about in a minute um a sub-sample of the birds were euthanized for organ and bone traits and another sub-sample of the birds were processed at a provincial processing plant so that we could look at meat and carcass quality and for the the birds that we weren't using for either the organ or meat data the carcasses were donated to a local food bank so they weren't discarded and we process birds at one of three ages because we know from other studies that that production and welfare parameters can vary depending on the weight of the bird and or the age of the bird we wanted to make sure that we were comparing both at similar weights and similar ages and so based on the breeder estimated growth rates we estimated the age at which either the conventional or the slower growing strains would reach an average light body weight of 2.1 kilogram and a heavier body weight to 3.2 kilograms and now this was taking into account the fact that we had a large number of strains with slightly different growth rates but also taking into account that there were limited days on which we could take the birds to the processing plant so arranging the study in this way allowed us to compare birds at similar body weights at what we call target weights one and target weight two but also at the same age at 48 days um i mentioned that the birds were were processed at a commercial plant and so in order for them to fit us in we had to choose the processing dates ahead of time and so working off the anticipated growth rates we chose days that worked of course with the plant to give us that 2.1 and 3.2 kilograms while the average birds were those weights there were differences between categories so in blue we have target weight one and you can see that the fast and the moderate categories uh strains of of birds were heavier than that target weight while the conventional and the slow burns were lighter than that weight similarly at the heavier target weight at target weight two um we found differences with the moderate and the slow strains being lighter than the fast strains there was nothing we could do about this because of logistics but whenever possible we did adjust the data relative to the bird's body weight or use body weight as a covariate in our data analyses overall uh mortality in our study was fairly good for production two and a half percent and there was no differences in mortality among the different categories and this value overall mortality and particularly for the conventional strains was was lower than has been reported in other studies and so this lack of difference may be due to a number of different reasons our on-site hatching incubation and hatching meant that there was no transportation between the hatchery and the farm we also used an experimental setting with small groups and had no disease pressure the study ran over a two-year period and we didn't have any of the trials necessitating treatment for for any diseases despite having antibiotic-free diets we studied the the birds foot and leg health as they're quite important uh welfare indicators and we looked at lesions on both their feet and their legs we looked at their legs for any any deformations and then we also looked at bone quality and bone strength we know that severe foot pad lesions and heart burns can be painful for the birds these lesions also can be an entry point for bacteria making them a major reason for condemnation or downgrading of carcasses so on this figure i have the percent of birds with severe foot pad lesions on the the y-axis and the categories by target weight on the x-axis and so there was quite a bit of variation um particularly actually at both target weights sorry um but there was no difference in the prevalence of severe foot pad lesions at the lighter target weight we did find at the heavier target weight target weight two that the conventional strains had a greater percent of severe foot pad lesions than did the fast strains however all of the strains really experienced high levels of foot pad dermatitis and these are these are the severe lesions that may cause pain the poor footbed conditions really right across the board in our study indicate that it was a challenging environment for all the birds the pens in our in our study had solid walls which reduced the air movement and led to wet litter because leg strength has been suggested as being a problem in broiler chickens we measured the bird's tibia breaking strength using an instron tensile machine we determine the amount of force in newtons per kilogram of body weight that is necessary to cause a break and the two target weights are on the x-axis here and the strains in descending order of growth rate and so we found at target weight one that the conventional strains had greater strength bone breaking strength than the other three strains with slow being the other three categories pregnant with slow being greater than fast and moderate at target weight 2 we saw similarly that conventional and slow strains had had greater strength than the faster moderate strains now bone strength was recognized as a welfare concern some 25 years or so ago um and it's obvious that the breeding companies have been successful in incorporating [Music] this welfare trade into their selection schemes without having a huge effect on growth rate so there is the precedent for the major breeding companies to include these traits that confer better welfare into their selection schemes um any study on brother welfare must quantify lameness and we know that moderate severe lameness is painful for the birds and about three to five percent of heavy broilers are unable to walk and traditionally lameness is quantified using gait scores and there's a number of different gait scoring systems but they generally include normal gait at one end of the spectrum and birds that are unable to walk at the other end of the spectrum and those two are fairly easy to recognize however it's the in-between stages that can be a bit difficult particularly when you're using streams that have natural different body sizes and shapes and have different temperaments for moving when approached by by people so we looked into the literature for some of the alternatives to examine lameness and mobility and so one of the alternative tests that we used it was the latency live test and clear weeks first described this um some 20 years ago and she found that the test corresponded with results of traditional gait scoring meaning that it's a validated test of lameness and so in this test the birds were placed into a shallow a container of shallow warm water and in this case we used two birds that were separated by a mesh barrier so that they could still have social contact with one of their their pen mates so we put them in in this video recorded them for 10 minutes and we measured the bird's latency to lie down in the water as a proxy for their stamina and their leg strength and so here are the results of the latency line test at the two target weights on the y-axis is time maximum amount of time they could um stand was 10 minutes and the results are quite different depending on the the target weight at the first target weight the conventional strains and the slowest strains have the longest latencies to lie longer than the fast and moderate strains and this was unexpected but it does follow exactly the trend in body weight at this target weight with the conventional and the slow strains being lighter than the fast and moderate strains now at target weight two the latency to lie increased with decreasing growth rates so the slow strains stood for longer than the conventional and fast streams when we considered both of those target weights together the conventional strains in the darkest blue at the shorter latency had shorter latencies to lie with increasing time whereas the other strains did not differ from target weight 1 to target weight 2 in their ability to support their body weight and so a shorter latency lie means that the birds either were unable or unwilling to remain standing an inability to remain standing may reflect either painfulness during standing um certainly one study found that administration of an and said increase the latencies to lie in broilers it may also reflect poor physical fitness for strenuous activity alternatively um birds may have been unwilling to remain standing so there may be differences in temperament or response to being in in the warm water that would have been captured by these results but we found very few differences when we looked between strains within categories and so because this test isn't something that chickens would have been exposed to during selection we wouldn't have expected that the differences in aversion to water per se to co-vary with with either body weights or growth rates the second lameness or mobility test that we use is the group obstacle test and this test was first described by gina kaplan and through it were able to quantify birds mobility within their home path so if birds are lame they may or may not be in pain depending on on the cause of their lameness however they may experience frustration if they're unable to access food and water or other important resources and so this test has also been validated with traditional gate scoring to indicate lameness in this test birds are in their home pen um the various colors we we painted them there that's not um we do do not have any blue broilers in our study or pink ones but those were painted for identification purposes and so the birds were fasted for one hour prior to the study and then we put this wooden obstacle that was 10 centimeters high in between their drinker and their feeder after um the out that was after the hour of of fasting then we put the feedback and released the birds from [Music] holding at the back of the pen just while we were putting in the obstacle and then we video recorded them for five hours so we counted the number of times birds crossed that obstacle for five hours with their feed on this end and the drinker line on the other end and so on here um this shows the the results of the obstacle test in the number of crossings over a five hour period um at the lighter target weight we we didn't see any statistical difference between the categories um the average bird crossed the obstacle about nine times over the course of five hours at the second target rate there was a significant difference between categories and that the slow strains crossed more often than the conventional or fast strength and similar to the latency the lie test fewer obstacles could indicate either an unwillingness or an inability to cross the obstacle as brothers are selected based partly on feed intake we would expect all of them to have a need to eat within that five-hour window however the added obstacle meant that perhaps some larger birds crossed less often either because they couldn't or because they didn't want to since we couldn't watch birds for 24 hours a day but we wanted to know what was going on with their activity levels we used uh triaxial data loggers or actical data loggers on the birds and these are are basically chicken fitbits um if you will and we've attached them to the back of the birds using like a back backpack strapping when the birds were 21 days of age and we kept those on until the end of the experiment and this this data logger has been validated for inactivity levels in laying heads and the bottom graph is is just an actogram of one bird at 25 days of age over a 12 hour period and i denoted when the lights went on in red here so you can clearly see the change in activity with lights on birds are are more active of course during during daytime hours on this graph we have the inactivity levels of birds from four to nine weeks of age and the duration of time inactive over the 24-hour period is on the y-axis and for all the categories inactivity increased with age however the conventional birds were more inactive than the slow and the moderate strains at four weeks of age and this difference amounted to about two hours of increased inactivity at five weeks of age the conventional strains were more inactive than the slowest strains by about one hour per day now the conventional strains also reach their maximum level of inactivity earlier than the other strains however that said all of the strains reached a similar level of inactivity over the course of of the study now inactivity levels don't tell us really anything about a bird's welfare we need to determine if birds are not active because they can't or because they don't want to be and that will for us in order to understand the welfare implications of it so it could be that inactivity corresponds with poor physical fitness or cardiovascular fitness or the differences could reflect selection for decreased activity that said inactivity levels themselves can lead to other welfare concerns if birds are having increased contact with wet litter or they are not getting as much load bearing exercise as is needed in order to better understand the implications of the differences in behavior we looked at the body conformation of the different strains on the left side is the relative tibia length of broilers at the heavier target weight and so what we found was that as the growth rate increased from slow to to conventional the length of the tibia decreased and this is counting for the body weight so at the same for the same body weight conventional had shorter legs than the remaining categories at the same time on the right we have relative breast weight accounting for body weight of the birds so as growth rate increased we saw an increase in breast weight so the conventional strains had large breasts and short legs and this may influence their their locomotor activity since their center of gravity would have been moved more cranially cranially than other strains of birds having short legs would help them control their lateral movement but it would also lead to inefficient activity so that inefficiency would could then perhaps lead to lower levels of activity to compensate for the greater energy demands so to summarize the results um we did find that many of the welfare outcomes were related to growth rates um in particular the inactivity levels and mobility we also found that there were there were few consistent differences between strains within categories that indicates that selection for growth concurrently selected for a number of traits that confer differences in welfare however brothers are often criticized for being inactive but we found that even the slowest growing strains spent 17 to 19 hours inactive and experienced severe foot pad lesions so just slowing down the growth rates on their own will not necessarily lead to perfect welfare now bird's willingness or ability to stand in water and cross an obstacle corresponded with their weight and growth rate depending on the the time that we did it um the results were not due to bone strength as conventional strains had the strongest tibia but also had worse mobility but because the conventional strains had the largest breasts and the shortest legs i also didn't present but they also had the smallest lungs the differences may reflect differences either in their center of gravity or in their cardiovascular fitness there were some positive messages for all of the strains and that we found really very little evidence of bone strength problems um long bone deformations or ascites which is a buildup of fluid in the abdominal cavity that can lead to heart failure and these problems i think were more prevalent some 25 or so years ago and they were identified so then breeding companies were able to successfully incorporate them into their breeding programs now i didn't present the individual string data today but we did find some differences between strains of similar growth rates in some of the traits which indicates that there's potential for selection for improved welfare outcomes with minimal impact on the growth rate now i talked a lot about broilers but there's another fairly major consideration that needs to be considered when looking at slower growing broilers and that's their parent stock the broiler breeders broiler breeders produce about 150 broiler chicks per pen and so in order to supply the huge number of broilers that are used that are consumed each year there's about 60 million breeder hens that are in production each year and brother breeders are in production for about a year so until they reach about 60 to 70 weeks of age and they're feed restricted from about two weeks of age so they're feed restricted because they have a similar growth potential as their broiler chicken that have been selected for fast growth and a large appetite however if boiler breeders are allowed to eat to satiety they quickly become obese and develop all the health and fertility issues related to obesity so really high mortality inability to walk things like that so they are feed restricted at times quite severely to ensure that they're not experiencing obesity but as a result they experience chronic hunger and they experience that for greater than a year as a result of that chronic hunger they develop things like feather pecking poor feather coverage as a result of the feather pecking they drink excessively which uses a lot of water and my team and i did quite a bit of work over a decade into feed restriction for conventional broiler breeders and chronic hunger and through our studies we found that you can make small improvements um by bulking of the diet or changing feed management but conventional broiler breeders are still chronically hungry and nutritional strategies for them are band-aid solutions at best so as part of this study we had the really great opportunity to study three slower growing broiler breeder female lines my as i said my team had studied conventional boiler breeders for a dozen years so we used the same housing and conditions for this lower growing strains as we did in previous studies for the conventional lines so that we could hopefully understand if there were a lot of differences among strains and we tested both the conventional broiler breeders in blue and the three slower strains in reds and oranges using a feed intake motivation test so in this test we measured how much feed the hens would eat relative to their body weight when they were given ad libitum access to feed over a predetermined amount of time so our studies with conventional broiler breeders for example here on the left routinely showed that the conventional breeds would consume about one and a half to two percent of their body weight during this test meanwhile the slower growing strains would consume about a half or a third of their body weight in addition to this we also quantified water usage we hadn't done that in previous studies but certainly as we consider the environmental footprint of slower growing strains we wanted to see whether there could be any compensatory um gains not in weight but in in less water usage and we did find that the slower growing strains cons used about a third less water at a similar or higher egg production rate now our paper on on laying performance is still forthcoming um but i think it certainly points to the need for more research into the welfare implications of slower growing strains for broiler breeders but there's also other other ways in which we can influence brother welfare that's beyond their genetics certainly the the better chicken commitment which is a proposal to improve welfare put out by a number of the advocacy groups includes areas to improve welfare including things like of course genetics but the use of enrichment lowering stocking density and using more humane methods of of stunning but there's also nutritional ways that we can use to improve broilers robustness and help them to cope with the stressors of production finally i do want to acknowledge that that people value different things um i'm speaking to you as someone trained in animal welfare science however in addition to welfare the discussion around slower growing broiler production needs to also consider the environmental footprint the global human population food prices antibiotic use and zoonotic diseases so dick julian who of you may know as a emeritus faculty at guelph um advised us a little bit on the start of our experiment um suggested some 20 years ago that it wasn't rapid growth alone that's related to the defects and and we hope that our results will enable not only the various stakeholders to evaluate breeds of broilers and determine which ones can meet their criteria but more importantly we hope that our data leads to advances in embroiler welfare through the incorporation of additional welfare traits within selection schemes i want to acknowledge our our funders global animal partnership the canada first research excellence fund through the food from thought program the ontario agri-food alliance and the anonymous breeding companies and other organizations that supported us and in addition to the people that i mentioned at the start this project was huge and included really a lot a lot of work and people and brain power and so i just want to put these names out there and say thank you for all of the work that you did in making this project uh a success thank you thank you so much so i think if you're unmuted you can really clap otherwise use your reaction thing and your yellow hands to um thanks there for a fantastic presentation the logistic complexity of this vast project blows me away and it's so amazing to see it all pull together