Be careful. The hawk that attacked my hen on Sunday was also back yesterday morning. Even though the chickens were locked in they went into panic mode.Glad I kept the birds penned, that hawk was definitely wanting them today. He swooped down in our front yard so low that he came about three feet from the ground.
Here the crows warn us when birds of prey are flying around and now the hens are panicked when they see or hear the crows : they associate it with the attack.