I buy from Rodent Pro. They consider a small rat 45-84 grams. Now I have to say, I have never weight the rats and that is a pretty big size range. I feed all my sub adults and adults 1 small rat every 7 days (and sometimes I give them a week break). On Adam's advice, I am going to keep an eye on the breeding size females and feed them extra if they appear to still be looking for food. Seems to work for me though!Originally Posted by daniel1983