I would go with a 40-45 g prey myself for a snake that size. She does look like she could put on a few grams. Most of my snakes at that weight were a bit more sausagey looking.

Bps are all about routine. And if they do not take the prey, waiting a week, helps to keep them on a routine, and it gives time to build up hunger. They get more food in captivity than their wild family members, so skipping the odd week is not a bad thing for them.

I always wait the week and skip the odd week just to keep them feeding strongly.

As far as not taking the rat... BPs are imprint feeders, some will switch over and some do not. Some take more time than others and some simply never do.

I have had a few prima donnas in my collection... and eventually they caves as mice are simply not on the menu in my house.

If you want to move up in size, you can try two smaller mice that equal a 40-50g prey item AKA 2x20-25g... chances are if she is used to bigger meal, you may be able to entice her to take two. Or you may simply have a one prey item per meal snake on your hands.

I would decide what you are going to feed and then stick with it, if you are switching to rats then you can try scenting the rat with a mouse, or keeping the rat on mouse bedding... a few tricks like that. Or you may have to just go tough love on her... as in "until you eat that rat you do not get any pudding!"

My experience is mostly with feeding live, so not sure what you are feeding... live or FT? FT, then you can defrost your rats on mouse bedding... I have put mouse bedding on them in the freezer as well.

Sounds like your husbandry is spot on *Congrats*.

Hope that helps a bit,
Bruce