I don't have a scale so I couldn't weigh my Pandora, but PetSmart was only feeding her one medium mouse per week, every week, for over a year. While she looked healthy and alert when I brought her home, she was definitely way too small for a BP that was over a year old. It took her awhile to acclimate. I'd feed her a mouse when she'd show interest, and a second one if I could get her to take it. Then when she got to eating regularly, the mice got bigger. Three weeks ago I got her to accept a small rat, and then again last week, and she finally blessed me with a turd that didn't look like it came out of a pigeon. She just ate her third small rat in as many weeks about half an hour ago, and I will try one more of that size next week before getting her up to medium rats.

I'm not really set up to measure length & weight on my snakes but I can see she's finally getting some girth to her. And tonight she gave me that "gimme another piece of food" behavior 15 minutes after swallowing the small rat (I won't give her multiple rats... I'll just start working her up to bigger rats).

I think these big box stores intentionally underfeed their pythons... just enough to keep them looking healthy, not enough to let them grow naturally or poop like they should.