I have 4 Bucks that I love dearly. I bought them together from a lovely breeder and they have always been happy, sociable, friendly rats.
Lately I've noticed that the dynamics have changed in their cage. They have a huuuge cage, lots of room! But one of them, Cracker, has taken to what I can only describe as bullying Onyx.
Onyx is never in the same hammock/sleepy space, he never eats when the others do... He tends to wait until the others are at the bottom of the cage before going to the top and vice versa. I have left it be up until now as I know naturally there will be a hierarchy but last night Cracker really went for Onyx and the squeak was ear piercing

The 2 other rats aren't as brutal with Onyx. Ra tends to go with the flow and is usually following Cracker. Ra can also be a bit of a bully and the last rat, Buck, seems to be more mutual. Although he's usually with Cracker and Ra this morning him and Onyx were snuggled in a box together.
If you've got this far - thankyou! And if you have any suggestions please help! One of the things I can think of is getting some Baby Ratties that Onyx can then form a bond with in a separate cage...?
They were born in May so are currently 7.5 months old.