Character: mackenzie (theredhare and demicoeur)
A female "pinto" horse (no white patches though, patches are slightly desaturated red and light grayish red),
character of TheRedHare and Demicoeur.
https://www.furaffinity.net/view/25029837/ says "Mackenzie belongs to me (FA username theredhare) and Demicoeur"
Character sheet at https://www.furaffinity.net/view/20863891/ (uploaded by TheRedHare)
and https://www.furaffinity.net/view/20863923/ (uploaded by SalKitten)