Reno, Nevada—The acting head of the U.S. Bureau of Land Management says it will take $5 billion and 15 years to get an overpopulation of wild horses under control. William Perry Pendley told reporters Wednesday several developments have made him more optimistic about his agency’s ability to eventually shrink the size of the herds from 88,000 to the 27,000 he says the range can sustain ecologically. Pendley says the agency adopted out more than 7,000 mustangs and burros captured last year – the most in 15 years. He says that helps clear space in government holding pens so they can accelerate roundups while scientists develop new fertility-control drugs. He says a new coalition of animal welfare advocates and ranchers is helping promote new solutions and Congress appears willing to help.