I'm curious, how do you handle a relatively wild horse at the age of 3 with their size and strength if they've had next to no human contact for those 3 years and ran wild?
I'd really love to know.
It's very interesting.
They've not had no human contact at all. You try to keep it to a minimum but for example a lot of yearlings are stabled for their first winter because they're still quite small and the weather can get really nasty in the winter.
If they're stabled they're usually kept 8-10 together in a really big indoor box. The people try to handle them as little as they can but they're fed of course, they are indoors and will be driven as a group to a turn out paddock if the weather is good and then herded back again.
2 year olds are often outside all year but their herd will be checked out regularly and in the winter fed additional hay. If you have access to the really remote and huge mountain pastures you only keep horses there in the spring/summer. There's a big annual round up to get them down from there in the fall.
Some people don't have access to those types of pastures and make do with ones closer to the farms instead.
Anyway the horses aren't feral, they just have little handling but most will for example have spent a winter mostly inside and they've seen people and been fed as a group by people etc.
It probably helps that the Icelandic horse has no natural predators in Iceland where they've been isolated for around 1000 years so they're usually not that flighty. They're horses and prey animals absolutely of course but their "OMG it's going to eat me!!!" instincts aren't quite as sharp as in some horses.
I've helped herd together a group of mares and young horses to have them all be microchipped (or their chip read if they already had one), and checked that there wasn't anything obviously wrong with them. We went riding to fetch them, herd them together and then drive into a pen, then from there they were made to go one by one into a squeeze chute where the vet checked them out and microchipped if needed.
I think a part of the reason apart from just "it's how it's always been done" for keeping them like this is that the horse culture (as in what we do with them and how we keep them) requires horses with very good horse social skills who know how to run in herds. When stabled even the riding horses are usually kept 2-3 to a box. In the summer it's expected that people can get together coming from different stables and areas with 3-4 horses each and immediately put them together to form a herd of horses 30-50 strong and then do a multi day horse trek where the people drive the extra horses as they ride and change horses 2-4 times a day to be able to keep going at speed for longer. Then in the evening this herd is turned out into a pasture and they're just expected to settle down quickly and be ready to do it all over again the next day. You usually ride between 6-8 hours a day in these trips.
Even fully broke riding horses are given around 4 months off every year. In autumn you take the shoes off and turn them out in big pastures along with other horses a lot of horse farmers will do these sort of "autumn pasture" liveries for you. Even people with land who aren't full on farmers often send their horses away for these pastures because they don't have the land or number of horses to do it on their land.
So in usually september, october, november and december you can't go riding at all because your horse is away barefoot with a bunch of other horses in the autumn grazing pasture, getting fat, out of shape and hairy but at the same time having a well deserved break and getting to be a proper horse again and it really helps with any mental problems they may have been developing. I for example never saw a weaving horse until I moved to the UK, I didn't even know that was something horses would ever do.
Some people will now do "pre-training" on their young horses. Basically once a year they'll take a few days and do a bit of handling with them, mostly getting the yearlings used to a halter, then the 2 year olds used to a bit and then a 3 year old used to a bit and saddle (but not getting on). But then after those few days they turn them loose again (except the 3 year olds) and don't work with them until next year when they then start with a slight refresher of what they did the year before and then add the new thing.
I think it's a very good way of raising a horse, you end up with a horse who develops his personality before being shaped too much by people, they're usually fairly self confident and know how to problem solve, good around other horses, pony easily, really sure footed and know how to do things like dig through snow to get at the grass underneath etc. they also usually really respect humans.