The reason she is being lifted is to prevent damage to her legs BB, as well as for her to eat and drink. She can't go a day with no water I think, so egg humidity needs to be dealt with another way. Traditionally (I've read) brooding boxes were bottomless placed on soil, with a hollow scooped out and hay added for nesting material. This was to collect damp from the ground. You could spray her underside to keep her moist, rather than the eggs. Temperature isn't so critical now, but I wouldn't risk spraying the eggs. She loses water in two ways- by urine and by transfer through the skin (not sweating). If she is drinking properly she will be able to continue to transfer water to the eggs. I picked a broody up this morning sitting on some previously bone dry kitchen roll sheets -they were rather damp.
