Probable Cause Corrective Measures Improper incubation temperatures (usually too high) Follow recommended incubation temperatures. Low incubation humidity Increase incubation humidity by increasing water evaporation. Embryos dried too much. Improper egg setting position or turning during incubation Set eggs with small ends down. Turn eggs at least 3 times daily. Do not turn eggs within 3 days of hatching. Heredity Proper culling and breeding practices will reduce problems. Slick hatching trays Use trays with wire floors or place crinoline on hatching surface. Improper nutrition of breeders Provide a well-balanced nutritional diet to breeders.

Avian Incubation and Hatching

Psittacine eggs should be incubated in the horizontal position. Ratite eggs are usually incubated vertically, with the air cell (large end) up.

Eggs should be turned every two hours during a 16 hour day. Eggs should be turned an odd number of times per day. Eggs should be turned 180 degrees at least once per day, and one-quarter to one-third turn each other time. Eggs should be rolled gently and slowly.

Abnormally shaped or sized eggs tend to have more incubation problems. If possible, these misshapen eggs should be pulled for artificial incubation, since the aviculturist will have more control of factors that may affect development.

Drawdown occurs when the air cell changes shape as the embryo, using the egg tooth, punctures the inner shell membrane and enters the air cell. The egg is designed to allow ease of exit from the egg, and the egg tooth is used to begin unzipping the egg shell in a circular manner, usually at the larger end of the egg.

The initiation of hatch occurs partially from the increased carbon dioxide level in the egg. This causes the embryo to begin twitching it's muscles, allowing the inner shell membrane to be punctured by the egg tooth. The chick then begins breathing the air in the air cell. As the carbon dioxide level begins to rise again, the muscularia complexus (the pipping muscle) at the base of the neck begins twitching again, facilitating the hatch. Abdominal muscles also begin twitching, which helps draw the yolk sac into the celoem. Leg muscle twitching helps strengthen the legs.