I've had good luck calling at night to get rid of our chicken killers , the outside lights on the house and barn give me enough light to pick them off in the shadows .I use a 20 gauge with buck shot and it works fine . I like Brad's idea , tie up a chicken in an open area for them to focus on and then do some distress calls and wait . I bet if he's loosing 2-3 a night he also has a racoon problem , we loose far more to coons than coyotes . At my place the coons usually start moving about 2 hours after dark and stay active until about an hour before sun up . If he has a compost area throw a bunch of table scraps in it and wait , bacon grease works really well for this . Good luck.