I hope your BP switches back. Took me 2 years to switch my Dumeril's off gerbils, no joke.

Switch your BP back to regular rats, as soon as humanly possible. I don't see any reason to feed gerbils or ASFs if your BP was perfectly content with regular rats. If they go off food in the winter, that's perfectly fine and you already know that, so I'm not sure why you'd even offer a gerbil.

I have males that only eat steadily 4-5 months out of the year, it's just how it goes.

I found ASFs far, far too temperamental for my liking. I have Norway rats now, and they are producing babies like mad. Yeah. They stink. But they save me a boatload of money. As opposed to the ASFs, who would take 4 months to hit maturity. Then they would take another 4 months to get up to an appropriate size to feed any of our ball pythons.

They are a monster PITA, in my opinion.