Coming from a hoarding case, he could have been malnourished, not enough exercise, injured, etc which could all lead to mobility issues which may make him seem like a senior bunny even if he is not. Sometimes you can tell via teeth if they are yellow as that can indicate a bunny older than five — HOWEVER, that is not always the case as a bunny that has been in a situation like Freddy has, teeth can be yellow even for a younger bunny. Ironically, even though my bunny was estimated around 6 when I got her and her teeth were dingy, but over time her teeth whitened a bit.
It is already difficult to to age bunnies, but when a bunny comes from a situation like poor Freddy has, it can even be more difficult because some of his symptoms may not be related to age, they may very well be due to where he came from. In time, with loving care, his movement and strength may improve quite a bit. If the bunny wasn’t able to move around much, his muscle strength will be quite poor, but that doesn’t mean that he can’t get stronger with better care with a new loving family.
I adopted a bunny who was originally in a neglect case. She was taken away from the owner by the Animal Care and Control. She had a funny walk because her spine was crooked. The vet said it could have been due to genetics, but if she was stuck in a small cage and didn’t move much and didn’t have good nutrition, it could have been due to that as well.
There also might be old injury or something else that is causing this, so it will be good to have the vet check Freddy over. Keep us updated!