I've fed some XL breeder rats to my big girl BP. Every now and then one dies and I hate to waste the bodies. It took her a few weeks to digest the first one, but she did it. After that her body was ready and she didn't have much of a problem with the others. Typically, depending on the size of the rat, one XL is almost a month's worth of food, so I wait at least 4 weeks before feeding her again and then start back with smalls. Guess that's the reason she's 2500~ish grams while all my other adult girls are under 1700. That and she's a spider morph. Never had a spider that didn't have a great appetite.

Don't think I've ever drastically underfed my snakes. I gave hatclhing BPs rat pinks a few times, but there's not much difference weight-wise between that and a hopper mouse. Just less hair.