I had to try the same experiment a couple months ago. I had a small BP who was eating 2 adult mice at a time. I went to get a hopper rat, but all that was available were small rats. So I bought one and gave it a go. The rat was probably 20% wider than the snake, but she took it down like a champ after just about 10 minutes longer than normal with no I'll effects. Kinda cool watching a python using every inch of its body to subdue it's prey.