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.
6. Record the day and how many eggs you've incubated on a calendar. You should be able to estimate your hatch date based on average incubation times for the bird species you want to hatch. For example, chicken eggs typically take 21 days to hatch, whereas many duck varieties and peafowl may take 28 days.alibrate the incubator's temperature. You must calibrate the incubator to ensure the temperate is correct and stable at least 24 hours prior to incubating any eggs. 1  Make sure to adjust the incubator's thermometer so that it will measure the temperature around where the center of an egg will reach in the incubator.