Auburn University Poultry Science Presentation Notes

Introduction

• Presented by Auburn University Department of Poultry Science
• Funded by Poultry Products Safety and Quality Peaks of Excellence Program and the U.S. Department of Agriculture

Hen's Reproductive System

• Consists of:
  • Ovary
  • Oviduct
• Unusual characteristic: hens have only one ovary (most females have two)
• Location of ovary: against the back body wall, left of the spinal column
• Oviduct structure: folded and stretches to nearly two feet in length
• Five distinct sections of the oviduct:
  1. Infundibulum
  2. Magnum
  3. Isthmus
  4. Shell gland
  5. Vagina

Egg Development Process

• Nutrients from food convert into:
  • One-third protein
  • One-third fat
  • One-third water
• Nutrients carried by bloodstream from the liver to the ovary
• Follicles in ovary grow yolk:
  • Largest follicle releases yolk for the next day's laying
  • Growth from <1 mm to 25 mm in 1-2 weeks
  • Follicle ruptures at stigma (area free from blood vessels) for yolk release

Oviduct Journey

• Infundibulum (funnel-shaped):

  • Catches mature follicle
  • First 15 minutes: yolk not covered by albumin, potential for fertilization here
  • Bacterial risks, e.g., Salmonella, can occur if contaminated

• Magnum (3-hour process):

  • Yolk covered by albumin
  • Spiral ridges cause yolk to spin, forming chalazae to suspend yolk in albumin

• Isthmus:

  • Shell membranes deposited around albumin
  • Egg shape initially more like a prune

• Shell Gland (20-hour process):

  • Thin albumin secreted to plump the egg
  • Calcium carbonate solution creates solid shell
  • Protein solution called cuticle deposited for protection

Egg Laying Process

• Process of oviposition: egg flips end over end and is pushed out by muscular contractions
• Hen's body temperature: 106°F; eggs laid in cooler environments (20-40°F cooler)
• Cooling forms an air cell between shell membranes, vital for chick breathing before hatching

Egg Processing Post-Laying

• Fertilized eggs sent to hatcheries
• Non-fertilized eggs go to:
  • Egg processing and packaging plants (for grocery distribution)
  • Egg breaking plants (for food products like mayonnaise, cake mixes, etc.)