I'm currently reloading shotshells by the thousands ... literally. There are a number of loads that would be good for coyotes. You need to get a Lyman manual and a catalog from Ballistic Products and find some loads that you like. Ballistic products does list some loads for coyote use.
EDIT TO ADD:
I just found this page. It's just an example of some of the things BPI offers:
http://www.ballisticproducts.com/load01-15-10.htm
