Fishermanpepin,
40-50 yards is to far out for trap loads? It might be getting a little out there, but I amn’t afraid to shoot 60 yards with them, let alone 40 yards. My avg. yardage at shooting them is probably 30-40. You have to figure that if you are standing below a big old oak tree (tallest tree in area) you know it probably is 30-35 yards up (maybe more) then if they are flying 10 yards above that…………you are at 40-45 yards and that isn’t even counting if they don’t fly directly over you. Glad to hear you shoot heavy loads at them, but I just use the $1.25 trap loads that I found on clearance at Wal-Mart to shoot mine. What it really comes down to is if you can shoot or not. Crows don’t hardly take anything to kill, so pretty much any amount of shot that hits the bird will knock it down. 
That is a good tip on resetting the decoys and having them come back. I have tried this the last couple times out and have had no luck what so ever. Not sure if the birds in my area are getting well educated or if they just don’t like my set-ups. Guess what works for one doesn’t work for another. My last time out all it took was a wrong tone of call with my mouth and they were gone. I then set-up with the e-caller for an hour and couldn’t get a thing to even fly by.
Cool pic………..glad to see you are cutting into the crow population. 