How to tell age of my bunny?
There is no accurate way at all to tell a rabbit's age once it is fully grown. While a vet can make a guess based on general condition, there's no guarantee it's anywhere near accurate. I had one rabbit who lived to 16 years old. When she was 15, she was still in such good shape that the vet told me at her checkup that if someone had asked him to estimate her age, he would have guessed she was three. She remained very active and behaved exactly like she had throughout her life until she dropped dead one day when her heart stopped. Older rabbits are not "lazy". Most remain quite active for life. If his testicles have dropped and he is in good health, his age is not relevant to the neutering procedure.
Just ask him... smh.
A vet may be able to tell. But if it’s energetic and not lazy then it’s probably a young one
Cut him in half and count the rings.