This is a huge problem for me to figure out . At this time, I don't know what I'm going to do, but I'm grateful to get the facts here. I will research different types of feed and be sure about wearing the mask for now. Thanks.
Do look into other feed. You may be able to find some that is gluten free and that your horse will tolerate. Perhaps make a call to the horse's vet. He might have some feed suggestions. Also be careful when grooming.
If no one else in your household can handle the feeding perhaps a neighbor, 4 H kid, or another horse owner might be willing and able to help out. Someone that loves horses might even do it in exchange for being able to ride one when they are done. If your horses will tolerate other riders.