Does anyone know if It is ok to feed a rabbit left over 12% pelleted horse feed? I have some feed left over (abt 4 scoops) and I don't want to throw it out if Leo can eat it.

Probably not. The horse feed is designed for horses and rabbit feed is designed for rabbits. Instead of throwing away the horse feed maybe try putting it in a bird feeder. The birds seem to like the leftover rabbit feed that I give them. My daughter has pet rats and thought that they could eat the leftover rabbit feed, come to find out they can't digest it -which is probably the case with a rabbit eating horse feed.

It's not alright. If your rabbit is mature you are only talking about 1/4 to 1/2 cup of pellets a day and they should be the highest quality possible. Horse feed is too little protein and the wrong kind of protein. Plus their are additives that are okay for a horse but may cause digestive upsets for rabbits. I wouldn't risk it.

Call the feed store or the vets office and ask them over the phone. It won't cost you and they will know.