Did you get the sale python from Petco like me? Yay pals card! LOL

One thing, I don't what your vet told you and I haven't taken mine in, but I was told by the manager (who took it out and sold it to us) they were feeding pinkies still! Ick. They are big enough for fuzzies, I fed both of mine 1ea last night and they devoured them! So you might be dealing with snakes that haven't been fed properly. Just an FYI since you got a Petco snake.
And yes, I got two! Short version, one got lost.