I assume you are looking at a guided hunt since in Alaska has a guide requirement for sheep. Alaska's season generally runs from the 10th of August to about the 20th of September. Go to the Alaska website wwww.state.ak.us as it has a bunch of info on hunting the state plus info on the distribution of sheep as well as guides that might help you pin down an area if you choose to experience this great state. Can't help you much on the big horns. Good luck on your quest.