I have mine out for the entire hatch. (Actually I don't even have the plugs...lol My sister lost them.) But a lot of us do leave ours open the entire the time.Hi, it is day 13 of my incubation and I read that at day 10 you should take out the red cap so that more oxygen gets to the babies. Do you need to do this? Is this wrong? Or should I just do that when they start to hatch?