I had my eggs under a hen for 17 days when she suddenly freaked and got off of them. I didn't have an incubator so I made one out of a styrofoam box and a 50 watt bulb. So far so good... it was registering a nice temperature, it was a good humity... until last night, day 20. The lid was closed on it this morning and when I got up (went to bed at midnight, checked on the eggs at 4:30 so 4 1/2 hours) they were quite warm and the thermometre had broken and was registering an error. I tested the water and the water (in a metal bowl) in their box registered 104... But again, it has just busted so it might be registering wrong. The thermometre can go up to like 400 or something F and 200C so I know it wasn't heat that busted it (unless I really...really...really... cooked those eggs). So I think it got to around 105 or 106 there over the course of 4 hours. I remember checking on it before bed and the number was going from 98.6 - 98.7 and back again over and over, so I figured it was maintaining. I'm thinking tops it was 105 for 2 hours... but probably only the last half hour... It's 6am on day 21... is the only way to find out if I cooked my birds to wait? Nothing I can do? It's my first ever batch of eggs in my life so I'm a paranoid mama hen and I'd just cry if I lost them on the last day due to my negligence. But I think I did... Edit: OMG sorry I was so panicked I forgot to say Thank you for helping me and say hello again on the forum! It's nice to see you guys again. Thanks for your help!