Those two horses have been mates ever since I can remember, and I believe if they were separated, they'd pine away and die.

You have noticed how low the partitions are between the boxes in the horse stable.

Father says you wouldn't put a lot of people in separate boxes in a room, where they couldn't see each other, and horses are just as fond of company as we are.

Cleve and Pacer are always nosing each other.
A horse has a long memory.

Father has had horses recognize him, that he has been parted from for twenty years.