While a 12 week old is less likely to be killed by a hawk, it happens.
Predators are out there, see them or not. I lost two full grown, hen turkeys to a fox that had never been here before.
I've seen an owl decide to kill a grown hen but be unable to do nothing with it.
In a truly free range situation, you lose stock. That's the way it is.
Six weeks is something a hawk would fine proper prey sized to remove in most breeds.
It's best to design hides, trim bushes to provide broad dense shelter, provide netted space and other safe zones - to provide SHINY objects to deter hawks like hanging CDs/DVDs.
Those help. But there is NO true safety for a free ranged animal, ever.
If you want safety you build a big, wire enclosure, with a top and dig wire and small mesh and hope.
6 weekers are already mingling with big chickens..they are doing fine.
I have plenty of hiding spaces live on 8 acres of woods.
They hawks have always been around, but I have never had a problem with them before,knock on wood. Its stray dogs that like to thin my flock...and they disapear once caught.
I'll probably wait a couple more weeks, have new seed in the veg. garden. Don't want them helping themselves to a buffet..lol
I've got 7week old chickens and they've been free ranging in the evenings now for the past few weeks. I leave the door open so they can go back in if they want and about 1/2 stay out the entire time, and the other 1/2 like to stay in the coop!