So I have run into a bit of a problem. I am on day 24 of incubating some mallard eggs and am getting ready for lockdown tomorrow. My problem is struggling to get good ventilation in my homemade incubator while maintaining temp and humidity. If I plug up all the holes except for one at the end of the incubator I can keep a nice temp of 99.5-100.5. The problem is when I try to get fresh air pulled in from outside by the fan by poking holes behind it; this drops my temp considerably by around 10 degrees which is way too cold. I have tried a larger watt bulb and I can get good ventilation, but then the problem comes in when I unplug the holes I can only get 25% humidity. So I was reading around and read a post by someone (who seemed credible/knowledgeable) who said that opening the lid during lock down to get fresh oxygen in the incubator won't shrink wrap birds or cause any hatching problems. Any body have any input or recommendations?