A book of two parts:

Horses at Home is about Nicholas and Clare, who look after their aunt's showjumpers when she's hospitalised with appendicitis. Nicholas and Clare know they have a lot to learn about looking after horses, but once they get Harvester and Jubilee home, they realise just how much they don't know. They don't know how much to feed them. They don't know how to clean tack, or how to groom.

Will they be able to learn what to do and not let Auntie Gay down?

In Friends Must Part Andy is overjoyed when Harriet moves just across the road from her home.

At first the two girls are inseparable, until the day when Andy decides she's had enough of Harriet always being late. The quarrel goes too far, and neither girl knows how to step back. They ignore each other as much as they can, despite going to the same school. Then they each get a pony. The ponies are best friends, but even that isn't enough for the feud to end.

Can the ponies succeed when their owners can't?

Horses at Home/Friends Must Part was first published in the 1950s when hunting was legal, and there are hunting scenes in the book.