My horse had such bad thrush when I bought him that I couldn't ride him for 3 weeks. We started off by putting on Thursh Buster which is basically just iodine twice a day. It got way better and I can ride him without any problems, but he has naturally very soft hooves and I live in Florida so the humidity in the air makes him even more prone to thrush. My farrier recommended that I apply thrush buster to the frog and then use Hooflex, which is an antibacterial and anti fungal hoof oil all over the bottom of his hooves and on the top. I ended up squirting a bottle of thrush buster into his hoof oil and applying it daily and he's gottten much better. The hoof oil acts as a barrier from extra moisture being absorbed and the thrush buster and hooflex's andifungal properties help clear up the thrush. Would recommend!
I use pure tea tree oil. My horse had thrush when I got him and I tried a lot of different things and it just didn't work and it just got worse. Tea tree oil is what worked for him, but different things work for different horses - I spent a lot of time trying a lot of different, more 'well known' products before turning to pure tea tree oil - wish I tried it sooner. I only use it as a preventative now, just a few drops, brushed into the crevices, once a week, sometimes more frequently if it's really wet and humid. It may be something to consider if nothing else works.
Our barn uses a solution of bleach and water. It's made on the weaker side, so it doesn't eat or harm the bottom of the hoof. We take an old spray bottle, and dump in a cap-full of bleach, then fill it to the top with water, shake it up really good, and off you go!! It does a really good job of keeping the thrush out of our horses' feet, and we spray our hoof picks off after so they're bacteria free as well!
Okay! I'm so glad you said that because that's what I've been doing I just waneed someone else's opinion, and yes I can practically stick my finger in her frog as well. Have you ever tried of have had any luck with the cotton ball method?
I find that iodine solution works miracles! We had a horse whose thrush was so bad when we got her you could practically stick your finger into her frog. Iodine solved this in a matter of weeks. We also routinely put iodine on all of our horses to prevent and cure any thrush that may be starting to develop.