They do knock the eggs around. Should be ok. I think most people advise to leave them in until the hatch is done, but I pulled them out as they were fluffed up and ready. One was especially mean and was pecking and stomping on a newly hatched chick, so I pulled him out before he was fully fluffed and he did fine. He was the only one who pecked like that. If you do have to open it, make sure your humidity is high or you are in a humid room and be quick.