I got a baby rex rat yesterday, not sure on the age. I got him from a non-chain pet store. The guy didn't seem to know how old he was. Someone on here estimated it to be a 5 week or so old male whose testicles haven't dropped yet. The pictures made him look a little bigger than he actually is, so I think he may be 4 weeks from looking at pictures of other rats. He's in a stage where his head looks a little big for the rest of his body. I'm not experienced though, so I have no idea. He eats pretty good (oxbow, the young version) and knows how to drink from a water bottle. I've been giving him goat milk like someone suggested to help him out, he likes licking it off of my hand and eating lab blocks covered in it, which seems to make it easier for him to eat. He's active and curious and not at all scared of being handled. But is it normal for one one of his eyes to be halfway closed? It doesn't have any porphyrin and the skin around it isn't red from what I can tell. He doesn't seem hurt. Has he just not completely opened it yet?