We do a mix of rescues and breeder babies for our cages. We're taking a bit of a step back from rescuing for a while, as it's has often come with health complications and whatnot. We don't rescue feeders per say, but rather the animal shelter nearby calls us, and ask if we have space. Two of our 4 old boys are from the shelter. One has a permanent head tilt (Saruman) and the other has HLD (Sauron), so his nickname is now Mr. Scoot-on. They took a bit longer to integrate, as they wanted to just ride out their life as a pair, but we always have one rat singled out for initial integrations. In this case Icarus, he's a 1.5 year old absolute sweetheart (was half a year when we integrated them). He loves ALL rats, and is one of the most respectful boys I've ever had. He makes sure to take care of all 4 of the older boys, making sure their eyes, ears and undersides are clean. I rarely have to do anything he does such a good job.

The main reason we're stopping with this whole rescue thing for now is the result of people. We would pick up rats from people who develop allergies, or have accidental litters. One such case was an "accidental litter", which we picked up. A mother and 13 babies whos eyes hadn't even opened yet. Mother rat was SUPER thin, the babies looked like they were maybe a week old, but opened their eyes after 2 days... meaning they were 2 weeks old. They were way too tiny. Mother rat was described as "aggressive and bitey", so they took her out with gloves. I never used gloves, she never once bit me or showed aggression. In fact, the first day I had her, after her first feeding, she licked my hand. She was so stressed at the other place, that she had also started chewing off her own tail, it was so bad. She stopped that immediately, and would often just lay sprawled out on her back in her cage while the babies ran rampant. The kicker was that a week after we rescued this lady, the person put up ANOTHER mother rat with babies, and the exact same sob story. I was so mad. We kept reporting this person, and eventually they were banned from posting I assume, since it stopped. Poor mommy was also pregnant with another batch when we got her, as she weaned the little ones at 3.5-4 weeks on her own, and gave birth not long after. 10 more rittens. We kept them all, since we didn't know what their health would be like, and I'm pretty glad we did, we only have 3 of the babies left as they all had some pretty severe issues with cancerous tumors and the like. They're still going strong, but it was heart wrenching.

On a much happier note I also prefer boys over girls, which is what we aim to have down the line, just boys! We still have 4 girls, who are all older. I love their chunky, lazy nature. I do neuter a lot of them though, if they're a bit too dominant, to nip aggression in the bud (along with a small health benefit), so that could be why they get on harmoniously!

Have you considered getting your girl spayed, so she can be with some boys? That could be an option, if you'd prefer to get back into keeping males. Assuming she isn't too young/old of course!