I am no Biologist, but, I think it depends on one big factor first. Are you trying to produce a trophy unit, or a "Largest Herd in the State" unit. I have noticed that some of the true trophy units in NV, UT, NM target " on an average 15-25 bulls per 100 cows, but these bulls are 4.5 (avg) years and old, maybe even 5.5-6.5 years old. I think CO goes for the larger herd numbers, duh. So there will be 25-35 bulls per 100 cows, but younger/lesser bulls. As long as there there habitat can support the numbers. JMO, don't shoot me if you don't agree!!! Hope I draw a Mountain Goat tag this year.