I decided the chickens were big enough to range freely in the pasture. Not knowing much about chickens, I waited for the cats to stop prowling around them for a few days. If the cats are scared off, they’re probably good to go.
The cattle are unsure, the goats don’t care, and the shepherd dogs have fortunately stopped chasing them around.
EDIT: that didn’t go as planned. They returned to the front yard to roost instead of the chicken RV. Re-boot is underway.