I just toss them out when I clean up everyday. I only have 1Blue Dutch rabbit, his name is Benny. He's a great fertilizer producer and sweet as could be.
Rabbit poo doesn't heat up as it breaks down so, it can go straight to the garden. It doesn't burn plants. I don't use rabbit feed pellets in my garden due to the salt contained in the pellets. I use horse pellets, instead.
I'd love to see your bunnies/fertilizer producers.