I put a hole adult rabbit in with mine (6) and take it out 2 days later depending on time of year ie flies or temp or whats left. (I aways gut what i put in) if you dont youll find out what i mean, and empty birds crops too
When you feed them sqeak a dog toy so they learn foods coming, then when working them take the toy with you if reluctant to exit give a sqeak should come out.
Defo want 2 of the same sex especially when seasons over to keep them active put new stuff in with them. (New smells and textures like grass, leaves, boxes and sticks)
My main worker still gets bored by