I adopted two three month old hairless rats, Julienne and Maurice, and I planned to introduce them both to Rizzo, my 10 month old man rat. Anyway, they all have outgoing personalities - Maurice is a little calmer than the other two, but he's not anti-social at all. I set them all in the tub with a bowl of baby cereal. There were no scraps, no hisses. Rizzo started bruxxing though, and there was a moment that they all tensed up for at least ten seconds. Other than that, they noticed each other, but it looked like they weren't phased with each other. They smelled each other and Julienne started grooming Rizzo a few times by the ear.
Then after about twenty minutes I moved them to my bed and they seemed great. Julienne was following Rizzo everywhere, Rizzo even seemed to be a lot more hyper than usual, but I'm not sure if that's anxiety.
I'm wondering if this is normal behavior. I've never introduced before, but I've read at least every introduction post here. This has got me stumped, I was expecting them to flip each other over and a little hissing, but nope, none of that happened. Is this normal?