Ooh, I haven't been online in a loooonng time. Copperhead, I don't know what pin firing is, sorry, so I can't help you with that :) All of the horses in the photos are buzkashi horses, for playing the national sport of Afghanistan. It's like a really really chaotic version of polo, played with a dead calf. There are two teams, nominally with twelve horse-rider pairs but in reality it can be up to a hundred on each team : the players try to get possession of the dead calf and make a circuit of a post in the opposite team's territory in order to score two points. Simply getting possession of the calf is one point. The horses are very quick and the best ones will even bow down so that the rider can get hold of the calf on the ground if that's where it is.
There is some serious money involved since it's a big prestige sport like racing is in the UK and US : businessmen and politicians often own buzkashi horses or whole teams of them, while riders try and get a good horse and thus ensure a place in the next season's good teams.
Natisha, in the summer there's no grazing and it hits 45 degrees, so yes, they're picketed all day with their feed in barrels. Early in the morning and last thing at night they're taken for a bit of a walk around to stretch their legs, then they're stabled for the night. The autumn/early winter is buzkashi season so they're put back into work, which means lots of long slow distance stuff and then sprints. There's grazing in the late spring / early summer so they're taken up into the hills a bit to eat. But they're still kept on pickets. With a good, proven horse costing upwards of 15,000 dollars, and no fenced land, you'd keep them on ropes too