I am noticing the same thing, not necessarily a huge difference but noticeable. I keep out protein/mineral tubs year round and they definitely seem to be hitting them harder lately. The grass is greening some and they are trying to graze a lot, I just don't think they are getting enough out of it. But they aren't hanging around the hay feeders stuffing themselves either... Spring fever I suppose. They want to be on grass, it's just not quite ready yet! I hope it is soon though, my hay supply is all but gone. Planning to hit the pastures with fertilizer in the next week or two and hopefully that will get things going strong.