Not a cottontail.
If you live in the US the wild cottontail and the domestic rabbits can not breed because they're different species. I'm not sure about the UK though.
I don't actually know what your bun is though. A broken chestnut agouti color, maybe? Really cute though!
Can you please include, as best you can, a current age and weight
5-10 lbs is a huge difference and can be the difference in many breeds of rabbits.
Even if you can try using a bathroom scale with you holding him, and then not holding him, and deduct the difference.
Odds are hes a mix of possibly a few breeds.
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