Ball python fasting. how do i know when she will be done?

i misjudged the size of a rat i last fed my ball python, who is about 2 and 1/2 years old and a little over 3 feet, and now she is refusing any and all food for the past few weeks. i have checked all the heating, humidity, and have cleaned the cage, but nothing has enticed her to eat. i intend to wait a week or so as to perk her interest more and try and wait this fast out, but i cant keep wasting money on rats, despite their smaller size now. is there anyway i can know when she is ready to begin eating again?

The short answer is no. After you have had the animal for a few years as an adult you can predict what they are going to do but there is no hard and fast rules. Usually by 2 to 3 years, if they have been feeding regularly they are ready for a long fast. Sometimes a couple weeks, sometimes six months or more. It seems they have some kind of trigger that when they reach the size they want to be for their age, they pretty much shut their digestive system down until they feel they need to eat again.

When a ball refuses a meal, you should not offer again for 2 weeks. If this happens twice in a row I will space out the attempts even further. It is times like this that it is easier to have more than one animal. I always have something that will take a leftover.

The best I can tell you is to watch the animal and see if it begins to display hunting behavior. Watch the weight of the animal. If you do not get a drastic drop everything is fine.

I actually have a coincidentally relative story.

My male BP who is roughly 3 years old went off food in early January. I offered roughly every two weeks 3 times. At that point, I knew he was on a food strike, so didn't offer again....

Until last night...

I noticed Saturday night that he was poking his head out of his hide, so thought maybe he's getting hungry. Sunday night, head out again. Now I knew he was hungry.
So last night I offered for the first time since March 9. Sure enough, he took it almost immediately.

My point is, nothing to worry about. Offer no more than every two weeks. If a few consecutive refusals take place you've likely got a snake on food strike.

Just keep your eyes open for her head poking out of her hide at night. Once you see that behavior on a few consecutive nights, go ahead and offer. I bet she'll eat then.