I had one chick hatch in my last batch with a pea-sized rough navel. 4 days later, the chick is one of the biggest, healthiest looking in the batch, but still has not lost his little red "bubble". I'm still waiting to see what happens. My question is this...Is there any factor in hatching that makes rough navels more prevalent, ie. temp, humidity, etc? I just set a new batch of eggs, and I want to prevent any problems, if possible. Thanks, ya'll!