I’ve been told too much sweet food will cause thrush. I was dealing with thrush with my 2 geldings also for over a year, but mine are on pasture year round. We have very wet winters here so just contributed it to that, but now I broke down once again to something else supposedly for thrush and for once I finally found something that works! It’s so amazingly, it’s like a miracle! It’s called No Thrush and the farm store and tractor supply here in Chehalis, WA carry it. You can also go online to nothrush.com and order it. I’ve been using it now for about 2 weeks although the thrush was nearly gone in 1 week. Friday I will cut it down to once a week for a while till the frog and the sulcus (I think that’s what it’s called) is healed and then on a monthly maintenance schedule. Hope this helps.