Feathering (horse)

Draft horse breeds such as Clydesdales often have feather

Feathering or feather is the long hair on the lower legs and fetlocks of some breeds of horse and pony. On some horses, especially draft breeds, the hair can almost cover the hooves.^[1] While nearly all horses will grow longer hair on the lower legs and back of the fetlocks at times, particularly in the winter, "feather" refers to the particularly long, luxuriant growth that is characteristic of certain breeds.

detail of feather or feathering

References

1. 1911 Encyclopedia: Horse