I am glad you might keep a few pigeons. I know I could never be without my birds, but I do understand when something bad happens like in your hawk situation, you can feel so helpless and depressed its tempting to give up.
I used to keep white racing homers and fantail doves in the UK. They are the best 'pets', so interesting to watch, breed, and lovely to see flying. When I had to move to Asia I had to sell them. It was the hardest thing. Especially as some returned to my home a few days before I was due to fly out, and their loft was gone.
I had some problems with hawks back then. When I was getting the attacks I stopped flying the birds for just over one month. The hawk must have forgotten about the birds, or got too hungry and moved on after that, so I was able to start letting the birds out again. I always made sure the birds were hungry and would return quickly to the loft, and not spend hours sitting about in rooftops - this is when my hawk attacks happened.
Interestingly I never lost any of the fat lazy fantail doves. They tended to walk about on the ground or sit on top of the loft. If they spotted a hawk they would sound their alarm sound and all dive into the thick bushes, or down behind the loft to hide. This they were actually more clever than the white homers!!
It might be your hawk is nesting and has chicks to feed, and has seen you flock as an easy meal. If you stop flying them for a while maybe the hawk will move on, and also once its chicks disperse it will not need to hunt so much. It also may migrate (depending of what species it is).
I saw a funny story about some pigeon racer guy who painted large eyes on the birds wings - like some butterflies have). It was intended to frighten any hawk that tried to catch the pigeon. I don't know if it would work, but I found the story quite interesting.
