Great shots, is that a california bighorn or a Rocky Mtn bighorn there are both species in Idaho State?.It looks like a fairly young ram from the shape and diameter of it's horns. The annuli, or the dark rings that grow on the horn develop during the rut. It's a combination of testosterone and lack of feeding, and searching for females that cause the annuli to form.The activity of rams increase dramaticly as the rut approaches, and during the height the rams are continuously on the move in the day light hour. The four year is the first real obvious annuli, due to maturity and the level of testosterone. Although North America sheep are sexually mature at 2.5 years of age. The lenght of the horn is not always an indication of age, horn lenght can be influenced by several factors, habitat, health, an increasing or stable or decreasing population. On older age class rams you can determine sometimes if they have experenced difficult times(bad winters, lung worm, ect...) by two annuli being close together, although the annuli do become smaller with age. After the rut and into the winter months the horn grows very slowly, and not until spring do you see alot of new horn forming. This new horn is easily identified by the colouration. Cheers, Ramchaser