If you got cows, just sprinkle some salt on it and feed it to them. My grandpa said he had a field that got rained on for a week straight, so he dump raked it into a big ditch. He said that winter the cows busted their butts to get down to that hay. Also you could put it into a ditch to stop dirt runoff. I started doing that with 2 round bales, then caught enough dirt to where they didnt work anymore, so I used square bales. Now all ive got is a slight depression, and no more hay bales
I throw some of it around my garages and barnyard (not where the horses can get it) when they're calling for ice rain or I have slippery frozen spots already on the ground. Once it gets walked on a few times, it makes for great traction, particulary if it melts a tad and then freezes again right into the ice.
I also spread a thin layer of it over thin muddy spots (but not where it's too deep and muddy, as it will just sink in); your boots will stay cleaner and you won't 'stick' so much.
Great for keeping for gardening also, like everyone says.
"The early bird may get the worm, but the second mouse gets the cheese in the trap."
If the mold is white, it is only good for compost, mulch, of some non-feed purpose, but if the mold isn't white, it won't hurt cattle or horses. Just don't give it to them as their only source of feed. I've feed hundreds of bales of moldy hay to cows and horses without the first problem due to the mold. If it's too moldy, they won't eat it.
I use it as mulch for the veggie garden mainly. In the spring or during a winter thaw I lay it down in the kennel and chicken yard to keep the mud to a minimum. I've also put them end to end and make a circle with them to make a brooder area in a stall when starting chicks. It blocks the wind and there are no corners for the chicks to pile up in.
We had the best garden we've ever had this last summer thanks to mulching with our old rotting hay. It kept the top layer of soil from getting scorched in the hottest weather, kept the moisture in the ground and keep the weeds OUT! It was great... we'll be doing that from now on.
DixyDoodle thanks for those tips; I'll have to try that.
Moldy hay is the very best stuff for all sorts of mulching
***** BUT *****
.... if the hay has been treated with certain herbicides it can kill most plants. Clopyralid, for example, has a half life of 11 years. When used by a grass hay, it effectively wipes out almost all broadleaf plants (weeds) for a looooooong time. And the grass takes some up, but does not die. But if you use that grass hay as a mulch, it will release the clopyralid as it decomposes and that will also be quite effective at wiping out almost all broadleaf plants (tomatoes, squash, trees, etc.).
AFAIK, alfalfa hay is always safe in this respect because it is a broadleaf.
If you see broadleaf leaves in the hay, you are probably safe.
Of course, any hay (grass or alfalfa) could be treated with insecticides or other pesticides that could still be on hay that are taken up by the mulched plants. This would be a problem only for those folks that are trying to grow stuff organically.
Just a footnote - we don't allow any chemicals on our land here so that's not an issue for us with mulching our garden with old rotting hay. We've decided to keep 1 bale each year for just this purpose... so we'll always have old hay to use for this.