If chickens have shelter, they can hide when needed. I think that smaller chickens are more likely to be prey to a hawk, because the small ones can be carried away.
All of my chickens are mature, including the big rooster. We have hawks around from time to time. Often the crows will run them off. We have seen them sitting on the roof of the shop, just watching.
If alerted, my chickens can usually reach shelter within 15 or so feet. The rooster stands out and appears to be on guard. I haven't lost any to a hawk, but I don't worry about it.
The rooster would probably be the first casualty.
Chris