Tricks to produce more rats?

[snakesRkewl]

Then it should really help that I replaced my breeding females with younger rats that are not from Petco.
(Was the only place to get them around here until I made a new contact)

I would think so, petco rats in my area are not something I'd want to breed unless I had no options.
Most of the time the petco/petsmarts in my area have nothing but fully grow black hooded rats that they ship in from who knows where...