Dear Editor:
The normative annual herd-growth rate is, at most, 5 percent. Gregg, LeBlanc, and Johnston (2014) found the average birth rate across wild horse herds to be just under 20 percent. But they also found that 50 percent of foals perish before their first birthday. Thus, the birth rate is just a temporary blip in the data. Starting with the net population gain from surviving foals (10 percent), and then subtracting a conservative estimate…
