Not 100% sure from the picture, but that appears to be a domesticated rabbit. People think they can "set them free", but it either leads to overpopulation (new litters every 30 days adds up) or starvation or worse for the poor bunnies.
If you could contact the Colorado HRS, I'm sure they would be willing to pick them up and try to find homes for them:http://www.coloradohrs.com/
It's very nice of you to give them Alfalfa. Poor bunnies.