My small flock of chickens free-ranged without any problems for almost three years. Then a pair of hawks discovered them. At first, I wasn't sure what was happening because a chicken would go missing every two or three weeks. Then I found one dead hen, partially eaten. The next day, I walked around the corner of the coop and saw the hawk, sitting on a second dead hen, eating her. Since then, my poor hens have been kept inside their coop full-time.
The hawks return to the coop multiple times daily, and shriek at the hens, hoping to startle them out into the open where they can be attacked. Once the hawks figured out that the hens were closed inside, they started landing on the roof of the coop, and on the sides, trying to figure out how to get inside themselves. They are relentless.
They also went for my 11 lb mini-dachshund. First one hawk swooped down to attack, but I was there and picked her up. The next week, BOTH hawks swooped together and they weren't overly concerned that I was standing right there! So now the little dog can't go outside unless someone stands right next to her at all times.