Notice the piece the of wood between the lid to relieve the heat.
Nice mix of Orpington's!
This is round 9 incubation an my wife asked me to take the incubator to the barn for the summer. My barn is constructed of tin and heats up pretty fast during the hot summer days. By noon the incubator alarm is sounding off because its too hot. Instead of lowering the digital temperature, I place a board between the lid to help adjust the heat and this work till early evening hours. Once the sun went down I had to remove the board and let the incubator do its proper incubation.
I had a 52% hatch rate using the dry incubation through day 19. I forgot to take the eggs off the turner until late of day 19. The humidity read 30-45% through day 19. When I went to remove the turner I already had a hatched chick completely dry and several eggs peeped. I removed the egg turner and placed 2 cups of water in the channels and this raised the humidity to 60-70%. I did have to place my board between the lid on day 20 and the chicks continued to hatch.
By the end of day 21 I had 25 chicks and it appeared all the eggs that were going to hatch was complete, so I remove the unhatched eggs and only had 9 clears with 13 dead chicks. I'm sure the heat raised too high before I relieved to problem during the daytime hours.
If you haven't tried the dry incubation method (no water added through day 18), may I suggest you give it a try. It works fine and a lot less mess with water.