Some hoof pics(see link below) & more info on diet & management would help.
My daughter's appendix made has terrible feet and this summers weather is not helping. We've had very hot days with thundershowers that produce about an inch of rain at night. The cycle of wet / dry seems to be wreaking havoc on her feet.
Unfortunately yes, constant or regular wet footing is not great for hooves. But if your weather's that reliable, keeping her in over night might be a good option?
Her walls are thin and her soles are a bit tender. She has never been overtly lame, but is heavy on the forehand and quite flat under saddle.
Have you tried her in boots or such to see if added sole protection made a difference? I agree that conventional metal rims aren't a great idea IMO. For one, you're further loading already weak walls and providing no support or protection for the soles, which sound like they need it.
Of your numbered plan... yes, absolutely tighten up the trim cycle. Especially when treating problems, it's important to aim at trimming often enough to *keep* feet well maintained rather than allowing overgrowth before 'correcting'.
Yes, studies have shown that biotin does indeed help hoof growth & strength, even in excess of balanced nutrition. Flax(fresh ground or stabilised) is also a good move, providing essential fatties which may be deficient. But there are a variety of other nutrients - mainly minerals - that are necessary for hoof health & often deficient/imbalanced in the diet. These include copper, zinc, iodine & magnesium. It's important to feed them in balance relating to other nutrients too, so a diet analysis is also important when working out what supps may be necessary. I love feedxl.com as a great resource that takes the confusion out of balancing diets.
I wouldn't bother with cornucrescine or tuff stuff. Healthy growth comes from inside & painting on topicals is only really helpful cosmetically.
The farrier said he trimmed her and left her soles a little lower to distribute the weight a little better and take some stress off the walls of her feet. Does this male sense?
Not sure. It depends on many things as to specifics & exceptions, but as a rule, walls shouldn't be allowed to overgrow the sole much at all - should be only a few mm or so longer than sole plane if that. And soles shouldn't *generally* be trimmed/thinned. So if the farrier had been leaving the walls too long &/or paring into the sole, that is likely to be part of the problem IME.