Sometimes if my pythons are on a self-imposed fast they will take live when they won't take f/t.
As an example-- I have a 1500gm pastel yb. I am not breeding Marilyn this season because she is a late '10 and even though she is large enough to breed and doing all of the big-girl things like fasting and bowl wrapping I do not want to breed her this young. Probably next year.
I tried for the last couple of weeks to get her to eat f//t, which she usually will. I have a very happy possum because she has been refusing. Today she refused a third time. I offered her a live rat and she took it within seconds.
Now, it wouldn't kill Marilyn not to eat for another month or so, but I want her to eat. I want her to be a good size and weight for next fall when I do allow her to breed. So she's getting live until she accepts f/t. I'm not worried about her getting bitten by a rat either. Marilyn is quite the efficient ratter. They seldom get out more than one squeal when she nabs them.