From my experience, once one is overly fat its hard to get them handling "right" again. We have a ewe lamb on our jackpot string now that has been chubby since the end of May and even with lots of sprinting, high protein supplements, and very little grain she just seems to maintain her very fleshy condition. Everyone loves her, but we only run her in the breeding classes now as she is way too soggy for the market classes and gets rolled pretty hard in those, but was champion breeding ewe at a show.