I've been reading about the pros and cons of harrowing to break up clods of manure and spread around the pasture. Some say that cows don't enjoy the smell of manure and will not preferentially eat the bright green grass around manure. They also say that it spreads pest larvae around the pasture. In the North East our ground is frozen. It doesn't seem right to let the clods stand until spring...Is there a right time to do this or not at all?