I had my two on the forage plus stuff for several years and it made little difference and they wouldn’t eat the Equimins so it was a waste of money. As they are on restricted grass and soaked hay over summer their feet suffer so the last two years I’ve fed pea protein at the request of my farrier when their feet (unshod) have needed that extra help. It’s cheap, palatable and I now mix pea and potato protein together as it’s even cheaper and does just as good a job. I get it from Rowan Barbary and you can see the difference in a few trimming cycles.
The specific hoof one for a few months, throw everything at is and then hopefully when you get better hoof coming down and the grass is growing again you can go for a cheaper on then.
Start off with a tiny sprinkle and build it up slowly and you should be ok.
I put mine on micronised linseed for the winter a few years ago. Not originally for their feet but because one was itchy and another was a poor doer. My farrier asked with no prompting "whatever was I feeding?" as their hooves had grown so fast and so strong.
I think I'd chat to farrier subtly about how he thinks the feet look, make out you are wanting to learn. We can't see how the feet looked before your current farrier, he may be making very gradual changes & is aware the job is not perfect?
It’s also worth saying that no farrier is going to do their best job on a horse that isn’t standing still, or is snatching.
It sounds like your current farrier has done an excellent job of building the mares confidence, and that isn’t to be taken lightly.
I would have a chat with him about her heels being weak, and her toes being long. It sounds like he hasn’t inherited good feet, and might need support to really push them in the right direction.
Her heels are weak, backing up the toes will help. But she might need some help with building structure at the back of her feet.
You can see the tubules at the heel and the toe aren’t parallel.
The best way I know to do this, would be to pull the shoes off and do it barefoot - which your farrier may be able to help with by the sounds of it.
But he may also be able to help with a shoeing package if you ask him about it.