I just hatched a batch and the same thing happened. I had two thermometers in there and *thought* the temp. was right on, but it must have been a bit on the hot side. No worries though, I had 22/24 hatch out and they all seem to be happy and healthy 3-days later. I put them in cartons to hatch and stuck a piece of rubber shelf liner over the wire rack and it all worked great.