I encourage the crows to come around. They will chase hawks and owls away. Several years ago before I put the netting over my pens, I have 2 coops that are open on one side which I have since put a tarp up over the open side, an owl killed several birds. I couldn't figure it out until I put a game camera up, what was killing the birds because I couldn't find any entry places, surprise... I do have video of it killing a bird.
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I had a dozen birds in this pen and the owl was picking them off. I had these three left to build my Rhode Island White flock back up with. The owl damaged one of the females comb. I took them out and put them in another coop and pen I could shut up, they were really freaked out, but with time recovered.
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