@starwindrider
It's alright! ^^ They can see each other every once in a while but if the mare has a herd her stallion will chase off any approaching males.
Fathers usually chase their colts out whenever they become sexually mature, so anywhere from 1-2 years although it can happen a bit earlier. Again, stallions will not let other mature colts/stallions near their mares. However, if the two are on their own I suppose they can join up for a while as a pair of bachelors essentially. Once they find a mare though, they'll fight among themselves and the winner takes the mare, leaving the other stallion behind.
Also,
-snip- and heights in hands only go up to .3 as one hand = 4 inches. ^^ Ex, 15.1, 15.2, 15.3, 16.0. 16.1, etc. -snip-