OK, so I have a rat colony for close to 5 weeks now. I have 8 females and now 2 males. I have 2-3 females in 101 qt tubs all setup properly. I had originally 1 male and 8 females and he immediately began mating with the females in each tub, I would let 3 days go by after visually seeing them actually mate. That was close to 5 weeks ago. One week ago, 1 Female started in what I thought to be labor, 1 kit was born (stillborn) my wife and I were watching as it started and sat there for close to 3hours and no other kits were birthed, I find this baffling that only 1 baby was born, and still born at that. OK, so since about 2 weeks ago I have been weighing the females to see if their is growth in weight everyday and NOTHING some of them lose 2-3 grams here and there but none of them are gradually gaining weight like you would think they were if they were pregnant. NOW 1 week ago I thought maybe its the male...... So I went and got a male from a breeder and he said this guy will do the job..... OK I removed the other male temporarily and put in place the new guy. He has mated with 3 of 8 of my females the 5 that he doesnt mate with he will sniff them and then go away from them. I think they are either pregnant from male#1 or just not in heat. I have left the new guy in for a week with these 5 females in one tub and he will have nothing to do with them... Can someone comment or give me some advice? Thanks... Oh also just to mention the temps in the room is anywhere from 68-74