I haven't read anything on this specifically, however, I've noticed that everyone seems to prefer to get the bps onto rats as soon as possible, even if they could still feed a larger sized mouse instead. Is there any reason for this? Around here, you cannot get rat pups (yeah, I goofed, I assumed that at least one of the petstores would sell them, but, they don't). You can get small adult mice and smaller, or you can get small adult rats or larger, no jumbo mice and no rats smaller than small adults. Are they switched to rats ASAP because it could be hard to switch them to rats if fed mice for too long, and you may end up never switching, and could possibly cause problems because of getting an adult BP to accept like three adult mice instead of one rat? Would I be ok to feed mice for the next month and a half until I can get rats and have feeders of the right size? If I have to, I could have a small order shipped in, but I'd prefer not to if I don't have to because of shipping costs, and I would only need a few to last until the breeding rats are up and going. Thanks in advance for any advice.