I myself would send them, 1500 is a good weight, might get some bonus money for prime carcasses, I think those heavier carcasses it's harder to hit prime. a lot depends on your last stage finishing ration.  if you were coming into spring with them I would say maybe hang onto them, mark wright has mentioned compensatory gain, and steins will put on a few lbs pretty quick in the spring. but going into the winter, there are too many things that could happen to those big boys, that could cost you some profits.