DONT TALK TO ME ABOUT CROWS.... been there done it you will NEVER NEVER shoot enough crows, i have guns, larson traps for crows magpies , hung dead birds in trees, they roost next to them, etc etc, do what i did get rid of the ducks trust me thats the only solution, if the crows dont get the eggs first the rats will, T here is only one remedy you have to lock them in untill 10 am... i had a pen to overnight them covered with bird netting, that worked but didnt stop rats.