Separating male and female rat litter mates - (Jul/13/2009 )
Hi. When should I separate male and female rat litter mates? On weening?
Rats reach sexual maturity at about 6 weeks, so you want to give yourself a good buffer. I think ~3 weeks would be okay, but I'd want someone to double-check that. I was a mouse guy, not a rat guy.
Rats and mice are the same. They should be weaned at 3-4 weeks of age. Some strains of rat (and mice) sexually mature as early as 5 weeks. Also if the animals are permenant breeding pairs, they will have post-partum mated and by three weeks after the birth of their litter they would be ready to drop their next litter anyway.