For my silkies, I have a pen covered with 2" galvanized poultry netting. Another pen that they are in at the moment (chicks are in the other pen) has plastic netting over it (from home depot in the fencing department).
You can also use bird fruit tree netting. I once saw a hawk come down for a silkie and BOUNCE off it as he failed to realize the netting was there.
If you are free ranging them, you must provide duck and cover places to hide- like lean pallets up against woodpiles, etc. Or install pallets on concrete blocks high enough for them to go under.
You must acccept some losses with free ranging, however (and it could get bad).
The plastic netting is not predator proof (climbing animals). For predator proof runs, use 1/2 inch hardware cloth. But during the day, I don't worry about predator PROOF. I close them up at night in the coops.
They will be free range so that is why I was nervous! I have a dog on the premises, but I don't know what else to do. There are flower gardens, trees, barns, and etc., but is that enough? I feel like I should buy a few extra chickens just in case.
I have owl decoys posted all over my yard and hawks still come and get the chickens. They realize the owls are fake after a while. I have 3 crows I raised as babies and they do a great job at deterring hawks. If you can start to draw the attention of crows, (toss out food, anything, kibble, table scraps, etc...) they will come at the same time every morning and believe me, you wont see hawks around.
You will need to make sure they have plenty of places to hide from hawks. Buying a few extra chickens doesn't hurt either. Also, don't let them free range until they are grown up some. Chicks really don't have it together enough to hide - I saw my 2 month old Buff Orpingtons hide from a hawk once successfully.
But those 5 week olds- they are helpless IMO. They think if their eyes are covered no one can see them!
Right now really seems to be a bad time. I had 4 hawks flying around and I am on a small lot in the city. I was sitting in a chair watching my hens yesterday,and I had no idea there was a HUGE hawk perched in the tree right behind me. It flew away when I got up,but had I not it probably would have attacked.
In the least a plastic fence run with bird netting over it is useful to slow the hawk down. I would not free range right now.