Male rats who have been introduced. Help!?

[Lizzy]

Well I have introduced my male rats properly and now in the same cage and have been for about 4-5 days now but my younger one stays in this little house a lot more then usual I think then he should. He does come out and play and eats and drinks but he is in that house for a lot of the time. My older rat still power grooms him. They eat together like they eat out same bowl thing they don't sleep together in their cage but when I let them out on my bed they end up falling a sleep together. My older rat like pulls his by his skin and I think that it's to power groom him but I'm not sure there's no blood or anything but my younger one does squeak. Should I be worried? Is my older rat just showing dominance? How can I get them to like each other more? Do you think my younger rat is scared to come out cause of my older one and if so how can I fix it? My younger rat is 2 months old and my older one is 7 months old.

 

[Bleekaboo]

maybe separtion might be good but it is most likely to do with domination putting animals in the same room or cage will always lead to one being the dominant one its very common amoungst many mamals