It's deffinately not that the rat is from a different source since you said he ate 2 from them. What size rats are you feeding him and how big is he? Depending on the size rat you might want to try a smaller rat. Leave him alone for a week with good temps and humidity then try feeding him (shaking/dancing the rat). If he doesnt take it leave it in the cage over night. This is how I got my male BP to start eating again. Check the rat in the morning If he didn't take it refreeze or throwout the rat. (don't refreeze more than once.) Don't worry because as long as you don't see a difference in his weight/size he is fine. A month is nothing at all.