That's exactly, how the Germans and Austro-Hungarians did!
They tried to cheer themselves by playing theatre, music, having lessons (like in School), making "tournaments" on catching rats, etc.
Firstly, after some heavy complaints, a local hotel at Narashino city (!) supplied food to the prisoners. After a couple of weeks, the Germans were allowed to prepare their own food, using their kept animals (chicken, cow)...
What impresses me most, is the change in behaviour during WWII. Remember, how winners treat their prisoners...