Crows can mob a hawk and persuade them to leave but, crows are just as likely to eat your chicks themselves. A cover is necessary. Hawks aren't the only things to hit from above. Raccoons often use a tree to get what they want. They can drop down from the branches and massacre a flock. Fox and coyotes can jump higher than you would think.
If you get a solid cover it can provide, protection also from rain and snow, and provide shade.
If you get a solid cover it can provide, protection also from rain and snow, and provide shade.
