I hate moldy hay and we bought 4 tons that has lots of bad spots. Yuck, I hope we don't buy from them again! Since I will occasionally have to give Uriah feeding duty, I showed him some of the sure tell signs that hay is bad. I have to give credit to Pam the owner of R-Way Farm in Eugene for really filling out my tips.
Moldy hay is BAD for horses and can cause them to colic.
1. It poofs mold spores. Did you ever see those puffball mushrooms when you were a kid? The ones that when you break them filter what looks like dust in the air? Well, moldy hay does the same thing if you hit it, tap it, drop it. Make note of the difference between DUSTY poof and moldy poof-they look different.
2. It looks like mold. Yep, the same thing the experiment in your fridge gets, I have seen it on hay.
3. It looks yellowed. Some of the hay that has not yet molded turns a yellowish color, often with spots of black in it.
4. It feels damp. In Oregon, stuff in the winter often feels damp, especially if there is condensation in your barn. But moldy hay will have a slightly heavier feel to the dampness
5. It is heavy. Do you have a bale that weighs twice as much but is the same size? Mold is a likely culprit.
6. It clumps together. Depending on the hay equipment, I have seen some very tightly packed bales, but when hay is moldy it doesn't break apart evenly as a dry bale does. If you have tightly packed hay in a flake, lightly use your fingers to separate it, if it goes easily it is unlikely mold, if not toss it.
7. It smells like mold. Nothing like an old fashioned smell test. Stick your nose in the flake (or bale), if it smells like blue cheese or the yogurt you bought six weeks ago throw it away.
Disposing of moldy hay-I throw it in the trash or on the burn pile. If you horses will have access to the manure pile don't put it there. I like buying hay from a reputable dealer or from the field (and I have watched the weather), if someone has asked you to pick up hay in the field 2 days after rain-think again.
No matter what, a wasted $10.00 bale of hay is cheaper than a vet farm call. Toss it!
Photo Credit Victor Geere