However, the correct relative humidity must be maintained until most of the chicks are out of their shells. Do not open the incubator unless necessary during the last 3 days of incubation. Turn them at least 3 times a day, except for the last 3 days when they don't need turning. When you turn the eggs, move them to a different part of the tray to minimize the effects of temperature variation in the incubator. If the eggs are not placed on their sides, they should be placed at an angle so the small ends are in the downward position.
Weekends often pose a problem for teachers incubating eggs at school.
Some teachers have found leaving incubators unattended during 2-day weekends has had little affect. Often the effect of not turning the eggs may be much less than that of the jostling, jarring, and possible temperature changes involved in taking the eggs home. It will make cleaning the incubator easier after hatching. Most chicks should hatch within a 24-hour period. Late-hatching chicks may lack vigor or be abnormal.