What age to free Range Chickens

[Shelbycobra]

We have nice fenced 1/2 acre area and I believe it is dog proof, ( 4 foot non clilmb) The coop and the run are within this area . My chickens are 8 weeks old and I am anxious to let them free range but I am worried they are still to small, and at risks from cats and hawks. How old, or big should they be, before I let them have run of a big yard?
My Friends chickes seem huge in comparison. I have two Delaware, 2 Rhode Islands, 2 Black sex linked, 2 Silver Wyandotte and 2 Orpingtons.

Thanks
Renee

 

[redoak]

By 8 weeks most cats will leave chickens alone. However you'll always have to worry about hawks

 

[stephenkeener]

I like to be sure they are roosting good. I've not only had hawk problems ,If I remember right I think I also had rat problems at somewhere around 6 to 8 weeks but this is usually a night time problem

 

[gritsar]

Mine were running around the yard for short periods of time, under constant supervision @ 2 1/2 weeks old. As they got older I gave them more and more time outside and less and less supervision. Now as adults I check on them a couple times a day and just keep my ears tuned to any unusual sounds. If there's a problem my rooster or one of the dogs let me know.