First, tonight when I was feeding my ball python his f/t rat, when he constricted it, the rats stomach came open revealing its intestines and such. The snake was still interested in the food but then later he let go of it. I took it out thinking maybe it wasn't good for him to eat the rat when it was completely open like that. Am I right or would it have been ok for him to eat it anyways?

Second, I was watching him move all around his tank tonight and was wondering if a 20 gallon long tank was too small for him? He is as long as the tank now. Would a 40 gallon be too big if I could get my temps right? Or is he fine in the 20 gallon?