I have modified my stance on that a little bit, after losing one in the last batch.I think I'm going to start taking them out when half of them are dry.The humidity comes back up so quickly, that I'm not worried about losing it in just a minute with the top off.I close the air vent until one third open.The owners manual said not to close it anymore than that, and my humidity holds fineSc believes in leaving them in until the hatch is done, I take mine out after they hatch and start moving. LOL It's one of those things that in my opinion you have to find your comfort level and consider your humidity.