Very interesting idea. I'll try to help as much as possible. The first step is to have an enclosed area to retain the heat. I am assuming that this part is covered. Second is to have a heat source. This too is covered. Third is to maintain a constant heat at 99.5 to 100.5 degrees and a humidity according to what you are hatching. This is where the problem comes in. He needs to control the temperature somehow so you don't end up with a bunch of boiled eggs for his lunchbox. The humidity part is easily done with water in a bowl or bowls and does need to be monitered by some sort of hygrometer. Please check on humidity levels for what you are hatching. LOL a dishwasher?.... An old refrigerator would have been my choice of appliance retrofit.
