Bill: The USDA Wildlife Services biologist, your local DVM or game warden would probably be better at giving you an age estimate on the coyotes in your area especially ones like in your picture if you happened to keep its skull for them to look at it. The story behind your coyote would be very interesting to hear if only it could have told it they are a fascinating animal. I spent a lot of years hunting down and killing the ones that caused trouble and got to see some interesting things along the way as well as enjoying the learning about them but there are those that are far better at some of it then I could ever hope to be. Along with the challenge of finding specific animals, I enjoyed learning and observing them there is no animal, in my humble opinion, better suited at surviving then they are. You are welcome, for what little help I could be.