I have an ultrasonic one, which i got for Molly, it just produces steam and Molly loved it. Actually i have a thought, if you have a grazing muzzle with the hole in the bottom, put that on, and then you can feed the steam through that???? It may be easier for her to accept.Thanks a nebulizer is the next thing to try if she won't tolerate the inhaler, we're lucky that our vet hospital is only 20 mins away and she can go in there for it to be done, or I have found the mask bit for $45 that can attach to a human neb, much cheaper than the grand for the horse one!