Yeah they get pretty ballsy like that, they are so smart sometimes too smart for their own good like this time.
I have contemplated for years trapping them like this around the dog pen but have choose just to shoot them instead on count of so many of the town dogs running around loose. Usually I kill one and I'm good for about 5 or 6 months. I got word that a property 1/2 mile directly behind my house sold that was being used as a dump for hog carcuses by a killing station. They had to come up with a different area to get rid of the unwanted waste. So I speculated the coyotes would hit my place a little harder than they have in years past and really start hammering the chickens. Sure enough they have made such a showing around here that I had to escalate my efforts of controlling the predation. I figure I'll let the chickens back out to free range after I have taken about 3 more in quick succession. The proper supplies should be in by tomorrow which will help get that foot on the pan