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.
Store eggs for hatching at 55 degrees F and a relative humidity of 75 percent. Eggs stored longer than 2 weeks may decline in hatchability. If stored more than a week, turn eggs daily to prevent yolks from sticking to shells. Incubation. Muscovy ducks require 35 days of incubation; eggs of other domestic duck breeds require 28 days. A chicken hen or female duck can set on 9 to 11 duck eggs. Place the nest where it won't be disturbed during the incubation period and provide a convenient source of feed and water. The nest should be checked at hatching time.