When buying an egg incubator look for the ventilation, temperature, humidity, hygiene and turning features in it. The incubation period has two phases, during the first phase the eggs need to be turned at a frequency.

While in the second phase the most species of eggs require 3 days of incubation without turning. During the second phase the eggs also require more humidity and lesser temperature but make sure to research the specific requirements of the species you are breeding.

Most egg incubators are designed with the first and last incubation period in mind. An egg incubator can be made at home also but there are a few factors to be kept in mind.

A steady temperature control is required and the incubation area should be free of drafts of air and direct sunlight. The temperature should be controlled in increments therefore a thermometer should be placed in the egg incubator to keep a check.

Place a pan of water in the egg incubator to maintain humidity and cut in vents and slots for extra moisture to move out when the moisture requires to be lowered.

Mostly an egg incubator comes with a built in egg turning mechanism but if your homemade incubator does not have this design then an opening to access the eggs for turning would help a great deal while maintaining the humidity. The floor of the incubator should be easy to remove and clean but do not use cedar chips as they are poisonous for quails.