What is the optimum incubation temperature and humidity for chicken?
The optimum temperature for chicken eggs during incubation is 37.5 degrees centigrade throughout the 21 days. It is the humidity you need to change as follows.
Day 1 to 10 maintain high humidity. This allows the embryo to develop faster.
Day 11 to 17 maintain low humidity between 40% and 50%. This slows the development in size of the embryo while it grows strong and sturdy. If the chicks become too big they cannot break out of the shells since they lack space to move.
Day 18 to 21 maintain high humidity of 55% to 70%. The humidity softens the egg shells making them easy for the chicks to break out of.
In addition to these temperature and humidity issues observe the following
Set fresh eggs, preferably less than six days old but certainly not more than 14 days old.
Set eggs from healthy birds fed on diet rich in vitamins. Chicks can inherit disease feom parents.
Introduce a new unrelated cock to the the flock every two years to reduce inbreeding. Inbreeding cause congenital weaknesses to manifest.
Also note the subtle differences in breed. Smaller birds like bantums hatch earlier and improved kienyeji come with their own little difference.