Avian Core -- CVM 6880

1. Know the anatomy of the avian female reproductive system
   
2. Know how eggs are formed and where each step of the egg formation occurs in the reproductive tract
   
3. Know the anatomy of the egg
   
4. Understand the importance of the dynamics of gas exchange across the egg shell
   
5. Know the relationship between incubation time, weight loss of the egg and gas exchange
   
6. Know the strategies used by various species to adapt eggs and incubation parameters to different conditions of humidity and barometric pressure.
   

1. Anatomy of the Egg
   
   1. Yolk
      
   2. Albumin
      
   3. Membranes
      
   4. Chelazia
      
   5. Chorioallantoic Membrane
      
   6. Air Cell
      
   7. Shell
      
      1. Composition
         
      2. Structure - Pores
         
2. Anatomy of the Female Tract (Sturkie, figure 16.1)
   
   1. Parts of the Tract
      
      1. Ovary
         
      2. Infundibulum
         
      3. Magnum
         
      4. Isthmus
         
      5. Uterus (shell gland)
         
      6. Vagina
         
      7. Cloaca
         
   2. Physiology of egg formation
      
      1. Ovarian Processes -- stages of follicular development
         
      2. Infundibulum
         
      3. Magnum -- albumin added
         
      4. Isthmus -- membranes
         
      5. Uterus (Shell gland)
         
         1. Plumping
            
         2. Mammillary Knobs
            
         3. Shell Formation
            
3. Incubation
   
   1. Ranges of Incubation times across species
      
      

      Comparison of Basic Incubation Times for Various Avian Species
      Species	Time to Pip	Time to Hatch
      Chicken	20.5	6 - 12 hrs
      Cockatiel	21	24-48 hrs
      Greater sulphur Crested Cockatoo	28	24-48
      Starling	17
      Peregrine Falcon	29	36 hrs
      Bald Eagle	34	24-30
      Philippine Eagle	56	30-45

       
       
       
       
      
   2. Temperature and Relative Humidity
      
      

      Temperature, Relative Humidity and Water Conductance of Egg Shell
      Species	Temperature	Humidity	GH20
      Pied-billed grebe	30 -32	>95%	High
      Chicken	30 - 32	60 - 70%	Intermediate
      Ostrich	30 - 32	20%	Low

       
      
   3. Average weight loss: 14% - 16% from onset of incubation to pip -- constant across all species of birds
       
      
4. Hatching
   
   1. Internal Pipping -- air cell breathing
      
   2. Rotation -- embryonic positioning: head under right wing, counterclockwise rotation
      
   3. External Pipping
      
   4. Hatching
      
5. Hatching Problems:
   
   1. Malpositions (6):
      
      1. Head between thighs - lethal
         
      2. Head in small end of egg - 50% mortality
         
      3. Head under left wing -- usually lethal
         
      4. Beak not in air cell -- slight reduction in hatchability
         
      5. Feet over head -- usually lethal
         
      6. Head over the right wing -- minor problem
         
   2. Dry chicks, stuck to shell: low humidity, incorrect turning, poor shell quality
      
   3. Wet chicks: incorrect humidity, incorrect turning, thick shells
      
   4. Unretracted yolk sac: incorrect temperature, low hatcher temp, high hatcher humidity, parental malnutrition.