Our chooks just roam around all over the place, in the house through an open door, in the garden, in the sheds, on the camp field infact anywhere within a few hundred meters, touch wood never had any fox attacks yet. We have a little dog that scents everywhere so this may help, there is also someone on the yard working every day in the daytime so they are quite lucky having human protection too.
I spose it really depends on whether a fox finds them or not. I guess we are lucky as the foxes I have seen dont seem to come round this part of the farm.
Ta
Baz