did you inject into the vent? there are two oviduct in the vent, one on the left, one on the right. the egg laying duct is on the left. did you put it in the wrong one?
DD used this last year on her cochin banties and it worked fine. They are white eggs and she got colored streaks on them for about 3 days. You have to look closely. I am not sure it would work with green, olive or brown eggs, but light colored eggs should definitely work. Try again!!