I'm not sure that there are more hawks here than other places. I notice them more than some people is more likely the truth. We have one main proper hawk here and that's the Goshawk. The Goshawk is about as bad as it gets when it comes to hawks. We have a few falcons but they very rarely bother the chickens. I've only seen one falcon strike from start to finish since I've been here and the falcon nerfed the strike.
The problem with the Goshawk, despite it's size (females have a wing span of four and a quarter feet) is they are superb fliers and normally hunt in the woodlands, flying between the trees. They fly low and fast and more often than not unfortunately the impact on strike is violent enough to give the chicken internal injuries even if the outside injuries are fairly minor.
Chick survival probability is age dependent to some extent. For the first few days the hen will call the chicks to her and protect the with her body. I rarely lose a chick under such circumstances. After the first few days the chicks mobility improves and they have enough wing strength to move quickly. When they get to this stage the hen ends them away from her to cover and takes on the threat directly. I don't tend to lose chicks at this stage either. In the worst case the hen dies. However, if a hen is going to fight a predator rather than run, for the predator this is probably the riskiest strike. A hen defending her chicks is going to be very risky for a hawk.
At three weeks to a month, depending on the breed and the mother, the chicks tend to wander further afield. It's as close to this point as is possible I like to see the chicks introduced to the tribe and learning to follow it. While mum may not be quite so protective the tribes rooster will at least give warning and this does actually help.
The worst stage is when the chicks have been integrated into the tribe, but are nervous around the senior hens. If there are a few siblings they tend to wander around together but often not keeping close enough to the tribe to notice the hens behavior if the rooster gives a warning call. They do however hear the general panic alarm and run to find cover. This often splits them up and this is when most chicks die.
) and left the other five with mama's (3 hens raising 5 chickies). Brahma mama is down to one as well, but it's a pretty good size. When she weans, it will be locked up with the others. It seems I was falsely accusing the barn cats of treachery...I left for work this morning to see a hawk sitting on the run roof 
