Joe- we don't feed protein except during exceptionally dry periods. As far as estimating age based on horn length; I have always felt that our aoudad get to 26" fairly quickly (3-4 yrs.) then horn growth, particularly length, slows dramatically; to the point that it is only 1"/year when you get to the 30" mark. Based on these numbers a 30" ram would be 7-8 years old. Because of the size of Deep Creek, the elusive nature of aoudad, and the uniformity of aoudad (tough to pic out and study individuals year to year) these numbers are really more of a feeling than hard fact.
I am curious of some others opinions on this question; anyone that has raised them where they kept a close eye on one individual ram would have a better idea of horn growth rate.
Recently got a photo of the big ram group: