I have the same problem with Ravens. They fly right into the shed and come out with full size chicken and turkey eggs. Not to mention the fact that they kill any ducks, young chickens, quineas, rabbits, and quail they can get to. I've had them kill quail, chickens, and rabbits that were caged in pens that had 1"x2" wire. Horrible beasts!!! And the way they kill the ducks is horrendous. They hop right along side the duck as it is trying to run away and peck a hole in its back. They even managed to kill a full grown African goose last winter. I can't free range any of my birds, except my turkeys, because of the horrid things. I'm working on a new poultry barn that will have a large completely covered run so that my birds can enjoy a semblance of free ranging. I've tried all kinds of things to keep them away from shiny, brite, flapping flags to scare crows to fire crackers and even a fake owl. They are too smart to be taken in by any of these methods. Good luck with getting rid of your crows. If you find something that works, let me know so I can try it on my Ravens.