There was a farm I saw on a Welsh tour last year Unfortunatly can't remember the name but will ask the friend I was with the weekend where it was but the herd I saw had well over 50 animals in it and there appeared to be 3 or maybe 4 more herds in other very large paddocks also on this farm there were at least large paddocks of yak about 30 in each.
If anyone knows the name of the farm I would be grateful, all I can remember is it's not far away from Betws - Y - Coed close to Snowdonian
The main reserve has no woodland as such, there are a few fenced off areas, that have been planted with native trees a few years ago, but this is basically an open exposed moorland, with a marsh area used by native waders etc
They are very similar, particularly when you can't compare the two species.
American bison have a bigger head held lower down, more shaggy shoulders, and a high shoulder hump. European is rather less heavily built, more long-legged, though still impressive.