Because I live in Canada Alberta where it is illegal to have live rats our only other options are live mice, hamsters or ASFs. My 2000g females get one adult in one feeding and some females can eat two in one feeding but because ASFs are not readily available, I try to keep many of my females on F/T rats but I have a few who refuse F/T. ASFs are a lot bigger then mice but not quite as big as a rat. An adult ASF is just slightly smaller up to the same size as a medium rat. My 2000g+ females grow just as normal on ASFs as they do on F/T rats.