Hibernating - older buns?

Hia my two older boy buns, Frasier (5) and Darcy (4 yr old Frenchie) are both in hibernation mode. Sleeping even more and not so demanding. Darcy is bit more lively than Frasier.

My two girls, Annie and Beatrix, both 2 yrs old, are the same as normal. Waking me up early for brekkie; playing; begging treats; wanting fuss etc.

Is it an older bun thing? All my bunnies are indoor free range

not really thought about it as buns dont normally hibernate.... it could just be thatt hey are less active as they are older possibly.... chelsea and sooty
(mums 9yrs and 10 years) are less active than they used to be....and coco 6yrs has been the shy retiring bunny until today when he decided to do a mighty run around everywhere!!! lol x

Willow was a frenchie who lived til she was almost 7 and she went through phases of sleeping loads then going mental another day.I suppose it depends on the bunny.She was like that when she was younger too cos of her size i guess.