When I incubate my eggs, I only put two small holes in the tub, one on each side, and put a sheet of glad press and seal wrap on the tub to seal it and then put the lid on.. Then, after the first month and a half of incubation I remove the glad press and seal wrap that I put on top of the tub before I put the lid on and put the lid back on for the rest of the incubation process. Also, I am not certain if you must leave the fan running 24 hours, but I do.