LOL, I was going to post that too... if you want to avoid anymore killings on wild animals, keep your cats indoors.
Seeing that they are "Farm" cats, that's a different story...
It's what they do
I'd take them to a rehab... or ask a veterinary to help you out or guide you and what not... at the very least, if you feel you are incapable and cannot care for them or have any other reason for not finding a rehab or aiding them that are beyond your capabilities (lol, sometimes for us, driving the extra 50-100 miles just to get a to rehab is costly) you can put them down at the vet's or by yourself (be careful, sometimes the vet's give them away to people who "feel bad for them" and they sometimes just do more damage to try and help than anything!).
Bunnies are hard to raise... especially itty bitty kits states person who had raised bunnies along side a breeder for ten years --> me. Sometimes, and most times for beginners, they just sort of shrivel up and die from lack of nutrition and care (not on your part, you're doing the best you can, but sometimes, your best is not enough - which is an ouch! I had to learn it that way). Sometimes putting them down is just more humane.
Make sure ya neuter/spay the kitties though, so this happens less often lol
Other than that, good luck!
THis is a tough job!
Oh just read your other post... BE CAREFUL of handing off bunnies to other people... if they don't know what they're doing, especially a rabbit breeder or farm (probably a BYB), they can infect their rabbits with what the babies may have... biohazard