Eggs need to be turned at regular intervals. The setter is the compartment in the incubator where eggs are turned automatically. This usually occurs for the first 18 days (in the case of chicken eggs). After day 18, eggs must lay still until day 21. This happens in the hatcher section of the incubator. From day 21 chicks will start hatching from their eggs in this compartment. Our combination incubators feature two separate compartments, the so-called setter and hatcher. The setter is the section of the incubator where the eggs go in for the first 18 days of the incubation process. Thereafter the eggs are shifted from the setter to the hatcher, where the eggs lay still until day 21 when the chicks hatch.