Horses are a species taht presumably exists in the world of Daventry (KQGS). The term horsefeathers is used as a curse when things don't well. And what is presumably a horse can be seen on a tapestry in Gwendolyn's room. The Purple Pegasus (pegasii) and Unicorns (KQGS) (not Majestic Unicorns) also appear to be horses.