You have to live trap it. Domestic rabbit would work, I suggested wild cause it, IMO would be more prone to not allowing itself to get caught and would be faster then a tame one.Try it at about 3 or 4 months, watch the dogs reaction if it looks like its not ready for this pull the dog out of the pen and try again when dog matures a little more. I would try to get the dog keen on scent b4 running with other dogs. Dont over do the pen thing. Every dog is different so you have to adjust to the temperment and maturity level of the dog as to when to do things (reading your dog).