I have a wonderful hen who is brooding right now. She is in a coop box in the larger coop. The first group of chicks hatched fine and she had them up under her and we took them out as soon as we found them and put them in a brooder. The last 2 chicks I think some of the chickens must have reached in and snatched them as soon as they hatched because we found the shells gone and the chicks on the floor dead. There is a big lip so they can't have fallen out. Is there a problem with covering the brooder box entrance for a few hours when we see signs the chicks are getting ready to hatch? Thanks!!