Getting friendly with the Neigh-bors

Well, , my children have adopted the horses next door as their pets. Conveniently, there are three horses - one for each of my boys. The boys have named them (I'm sure they already had names). Koby's horse is named Mr. Mischief, Spencer's is Zorro and Clay's is Mr. Messy! The horses seem to actually like my boys. Whenever they come out, the horses come over to see them, and they stick around whether there's food or not! Clay loves them just as much and will come inside and ask for food, then take off with it to feed the horses. The other day I was cleaning while the kids were outside playing. I finally went outside to check on them after an hour or so (I could see them through the window so they weren't totally neglected) and found that they were brushing the horses! Koby had a plastic brush from a stick horse we have, Clay had some scrub brush from the garage, and Spencer had a comb from inside our house. Those horses sat still while my kids stuck there hands through the fence and brushed the stickers off of them. Koby tells me, "You can't brush their mane because it gets stuck, see?" Then tries and gets the comb stuck and pulls it out while the horse didn't budge. They told me that they don't ever want to move again because they love their pet horses so much!