I hate thin soles. First thing to address is to make sure that the farrier’s trim job is not inadvertently causing the thin soles or the soreness… How long is your mare’s toe and are her heels underrun? The longer the toe the thinner the sole, in my experience.
My gelding clocked in at 5mm on x-ray :eek:
He also was funny the first trim with pads. It’s possible your horse does not like the sole/ frog pressure of the pad - if the soles are thin enough, pads can be uncomfortable the first few trims. I’ve never done pour-in, but I had good luck with leather pads for two different TBs who were out 24/7. My current gelding just shears his sole like no other, even with pads - I’m curious to see what his rads look like now that we’ve switched farriers as I do believe that was part of the problem.
Have you tried rim pads instead? They go around the shoe and basically add a little more clearance. They’re good for horses who need their sole off the ground but can’t tolerate sole or frog pressure. Also, I’d be discussing with farrier the findings and let him know under no uncertain terms should he be removing any sole.
I have not found any issues with thrush - my gelding has been in pads for 2 years now. We pull his shoes in winter since he has it off but he goes back in once he is in work. The only issue I have is occasional mud balling inside the pad, but that’s because he is out 24/7 and it is very rainy in spring for us. We will pack with magic cushion before nailing the shoe & pads on.
One other thing I do is fill up a small oral syringe with a little durasole - put it between the sulcus grooves of the frog and squirt in under the pads. I do this probably every two weeks. I think it helps.