This is similar to the pregnancy period of a woman, which is closer to around 9 months or ~260 days. However, actual gestation period of a cow can range from 270 days to 295 days, depending primarily on breed[s], age, body condition and nutritional health.Gestation period is also controlled by genetics, but not rate of maturity.his is similar to the pregnancy period of a woman,  which is closer to around 9 months o â¦ r ~260 days.    However, actual gestation period of a cow can range from 270 days  to 295 days, depending primarily on breed[s], age, body condition  and nutritional health.
Whereas fertilized chicken eggs usually take exactly 21 days to hatch, most duck eggs take 28 days, apart from Muscovy ducks. As a general rule of thumb, the eggs of Muscovy ducks take 35 days, but once again, it can vary slightly depending on conditions.
EGGS A bald eagle egg is slightly smaller than a domestic goose egg. The chick will measure 4 to 5 inches at hatching and weigh only a matter of ounces. Bald eagles incubate their eggs for about 35 days.They begin incubation as soon as the first egg is laid.The second egg usually appears within 36 to 72 hours after the first. Occasionally a clutch of 3 eggs will be produced.ald eagles incubate their eggs for about 35 days. They begin incubation as soon as the first egg is laid. The second egg usually appears within 36 to 72 hours after the first.