Most predators are far and in between anymore in the Western US. If
predation was a big factor I believe we would not have to worry about
the high numbers of wild horses that prompts regular round-ups to
reduce the number of feral horses and I think we would also probably
see a higher percentage of laminitic wild/feral horses as they get
caught, or at least see some evidence in their hooves.
If wild /feral horses also had more laminitis/founder issues, I think
that would also naturally reduce their number more.
I believe that the life span in feral horses is primarily affected by
how many babies a mare has had for example, how long their teeth last
for chewing and any traumatic injuries that may occur.
Also, Pete Ramey mentions in his DVDs that wild horses are not known
to founder. In addition, there's a documented story of a stallion who
had a break in one of his front legs. He actually healed completely
and had to be caught to get the hoof trimmed on the leg that was
broken beore, since he had not used it normally. Yet Barbaro
foundered with all the medical support he could possibly get.
--- In EquineCushings@..., "Joan and Dazzle"