No doubt that it can and is done all the time...If you read any of the interviews of the old time dog-men they had about a 2-3 month keep on their dogs before they went to a match. Some of these old dog-men were masters at this and were very sought after to condition dogs for matches. Not sure how much they made doing it but I am sure they got compensated well for their efforts..These guys would pull weight off dogs to make match weights and the dogs looked like ripped spring steel with skin stretched over them before these matches...These shows would last upwards of 3 hours sometimes...I would search some this forum for some advice.
http://www.game-dog.com/forums/