I have to jump in here since I live in the middle of mustang/feral horse country. There are various groups studying mustangs, for various reasons.
1. The BLM studies them to try to minimize their numbers in as easy a way as they can, which is why they have studies, ecological impact.
2. Barefoot trimmers of various trades try to study the wear of mustang hooves to better understand the natural hoof. They are not trying to emulate the mustang hoof. Just to bring domestic hooves a little closer to *less problems* and better understand the proper function of the hoof. MY horses in Arizona, all Quarter Horses and Arabians, went without shoes in summertime and we discovered that their huge sandy wash "pasture" if you will, and the rocky, steep hill to the barn and feed wore their hooves absolutely beautifully. Just like a mustangs. And that is when we decided to go without shoes. Never had a problem after that and we rode rough country. Every horse is an individual just like people,, some still need shoes, they carry unnatural weight, etc. etc.
3. I also must interject this: Many mustangs live well into their 20's. Most of them are fat and healthy, they lose weight and look terrible after the stress of capture, being penned up, and hay they are not used to.
4. Everything about the feed comparison between mustangs and domestic horses is very well stated here.
5. They are not rounded up every few years and removed. The BLM has a lot of mis-information out there on purpose. There IS NOT an excess of mustangs on the ranges. Check out the territory yourself and you will see a lot of cattle but not that many horses. It takes them weeks to gather the hundreds they do wasting your tax dollars to support a huge number of these horses in holding pens forever. Many die in the course of the roundups unnecessarily. It is well known in these parts how corrupt the BLM branch of the govt. is. The whole subject is a complicated can of worms, and the losers are the horses, and the taxpayers.
6. If mustangs have physical abnormalities, they sure wouldn't last long, especially since we now have wolves out there. And a lot of the "mustangs" people see, aren't. They are bred from a BLM mustang by someone. They also are not a breed, and the only *papers* they have are the BLM adoption papers to match their freeze brand.
Go on facebook and take a look at Mark Terrell's work on mustangs. KBR, Mustangs 4 us, there are many sites to inform yourself.