This is my reply to a similar question before -
Handle them a lot, get them used to you feet, the dogs, the nets, tubes, tunnels, the grass, going in the box, getting collars on.
Pick them up from the mouth of tubes gently and calmly, so they don't mind your hand reaching for them at the mouth of a hole.
Feed them and water them well, maybe introduce a whistle when you feed them.
Do not starve them, thats stupid, pointless and cruel, and do not throw them live bunnies, it's also pointless, cruel and just weird.
Enter them, in small, occupied warrens, maybe behind an expe