I'm currently trying to make enclosures for several mobs, and rabbits were the first ones I tried. It is so extremely annoying to get them and keep them alive. For one thing, there's a 90% chance they'll get stuck on a block they're trying to jump on, whether I have them on a lead or am just holding a flower so they follow me. It took about an hour to get them over just one hill because of this. They can also get stuck inside random blocks even when I'm not trying to lead them. (Shown in picture) They're also much too weak. Jumping off just THREE blocks kept killing my rabbits. I have some tiny 3-block hills in the enclosure I made, and they keep dying by jumping off them. I'm debating just not having a rabbit enclosure at all because it's way too difficult to get them in and keep them from dying.

Solution: Make them jump blocks properly and give them more health.