Hard-working mom defends herself and newborn foal against some bachelors in this FB video, filmed in 2015. Looks like the Pryor Mountains, confirmed by this post at Wild in the Pryors.
Western Horse Watchers Association
Exposing the Hypocrisy, Lies and Incompetence of the Wild Horse Advocates
Western Horse Watchers Association 
Hi. Thanks for the referral. Here is a link to the complete story of the mare and foal. https://wildinthepryors.com/2015/07/05/new-life-and-a-guardian-angel/