The slow boy

So! I got Bruce and Robin, my boy ratties about a month and a half ago but I've been noticing something in Robin's behaviour and I don't know if I should be worried. Bruce is my most active boy, in his out time on the room he runs a lot, climbs up chairs and into everywhere he can get his paws on. Both boys have settled down pretty good and I think they're quite used to the room and to me (They're never scared of me picking them up or anything like that). Then we have Robin, he's a bit bigger and chubbier but not overweight and he's a bit... slow, if you will haha he runs much less than his cage mate, he still plays with him a lot but he spends more time sitting in my lap for cuddles or inside my shirt than climbing.
He's a super lovely boy and he doesn't look sick at all, his hair is shiny and soft, his eyes are bright and he's not wheezing or sneezing too much (He sometimes sneeze when he gets inside my shirt but I think it might be because of the body sprays and deodorant and all stuff going on ^^) Do you think it's just his normal behaviour or should I take him to the vet for a healthy check? Thanks for reading!

Everyone has different personalities, so as long as he is healthy otherwise, it may just be 'him'.

I thought so Thank you Joanne!

Since you brought it up,
scent can irritate airways and make rats ill so if you use products that have a scent, you might want to reconsider

I had a cage of 7 (currently that cage is down to 3, the rest past) they ranged in weight from the 400 grams to just under 1000g. Yep, my Peanut is a slug, but a big cuddly squishy

Sounds like part of their personality. One of each kind is sweet.
Ya, for fragrances, I stopped wearing hair spray because it made my rat sneeze.