It’s not a problem involving random sampling, statistical inferences and confidence levels. The characteristics of the population are already known.
Just get the forage allocations for all of the areas not managed principally for wild horses and burros (which is most of them), add the forage amounts for livestock and divide the sum by twelve.
Add that result to the current AML of 27,000 and there’s your answer.
FOIA requests may be required.
Water may be limiting factor in some areas.
Western Horse Watchers Association 