(Alan Rogers | The Casper Star-Tribune via AP, file) In this Oct. 21, 2013, file photo, wild horses roam the Jack Morrow Hills area of the Red Desert in remote Sweetwater County, Wyo. Federal land managers say it will take 20 years and cost more than $1 billion over the first six years alone to slash wild horse populations to sustainable levels necessary to protect U.S. range land.