In the past, I have hatched a lot of chicks and I usually have problem that hatched chicks playing soccer with unhatched eggs. To prevent this to happen, I usually open the incubator or hatcher to get the chicks out. This cause problem to chicks which were not fully fluffed up were really weak. Sometimes they died in the brooder with so many chicks. Some couldn't hatch because of lack humidity and the membrane stuck to their feather. Sometimes, I could not stop myself opening the incubator, I think you know what I mean. To solve this problem, I made a way for hatched chicks to drop down the tray beneath the egg trays. I also made a door on the side and provide light there to invite hatched chicks to go to the escape door into the temporary brooder. We then can open the door of that temporary brooder which I called escape box and put the chicks into the main brooder when they all fluffed up. This way will help to maintain humidity level in the incubator / hatcher for most if not all eggs to hatch and will increase the chance of hatching. I hope this idea will help some of you when design your incubator.
This incubator designed to fit the GQF trays. At first, I tried 2 computer fans and later on changed to 3 but the air flow was not enough, so I put a larger fan in so the shape of the incubator is weird.
These are the fans that I have tried.
This is separate water door so we don't need to open the whole incubator to fill water.
This is escape box for the chicks to stay before moving to brooder