I dont think there is a standard that could always be considered fair. I saw 1100 small, common quality 4x5 round bales of grass hay at a farm sale Jan 1 bring 65-75 dollars per bale. At that price, 20 dollars for putting the hay up would be too cheap. The past 5 years, those same bales have sold for 8-12 dollars per bale and 10 dollars to put it up is too high. Over the last 5 years, there has been alot of hay rot in our area because grass hay was selling from 8-15 dollars per bale, depending on the size and quality. The farmers who put the hay up themselves, sold it for that. The ones who hired it put up, said they would rather let it rot, than to sell it for less than it cost to bale it. So, it rotted. When hay is high, people will bale hay on the shares. When it is cheap, no one will bale on the shares. A couple of years ago, the only guy around here that would bale on the shares got 75 percent of the hay.
There is also a continuous cycle that goes on. With sky high hay prices this year, alot of farmers will decide they can raise hay to sell to make a living. Then, if it rains, there is way too much hay and the price bottoms out and they cant sell it, then they go back to buying cattle and then the hay is short. It is an unending cycle, but all of it depends on the weather, anyway.