What is the minimum temperature for the inside of the hutch.

From - https://rabbitwelfare.co.uk/

In the wild, rabbits live in underground warrens where the temperature does not vary much (around 10°C) between winter and summer. Pet rabbits don’t have this luxury so owners must make sure their rabbits have permanent access to a sleeping area that is kept constantly sufficiently warm, dry and draught free. And of course, they must have a companion because sharing body warmth is a vital part of a rabbit’s winter toolkit.