ACK! Had this typed and got booted
Here's Rusty's hooves in December, 2007. The lines were drawn by a profressional trimmer to indicate the hoof discrepancies. Note the "dish" on the inside of the right hoof, similar to the OP's horse, indicating he was not balanced and needed trimmed differently. I wasn't riding him during this time period due to my own nasty injuries, so things got away from me
These are May, 2009 because I can't find this year's pics and are at five weeks BEFORE the trimmer came that morning.
This horse also went thru a major diet change in 2007 as that was the year another of my horses was diagnosed with insulin resistance. As a result, I quit feeding grain and grain products to everyone. All they get are soy-free vit/min supplements, Omega-3 Horseshine, and a small bit of pelleted rice bran because they love the taste and therefore eat everything without issue.
Because of that left hoof being mildy clubbed, it is an on-going issue keeping him balanced. Toe cracks are always making an appearance but I also know how to trim so I keep up with him between the five-week visits from the Trimmer.
He is splay-footed because he is a Tennessee Walker - splay-footedness is a typical trait but some TWH's more than others. This Guy is now 15+ years and has been with me since he was 2-1/2 and barefoot most of his life. He has hooves tough as a goat, I have trail ridden him everywhere and he's never come up sore or lame.
Hope all this information from everyone helps