Coons out during the day doesn't mean they are necessarily ill or any more dangerous than at night.
Many normally nocturnal animals will hunt during the day if the need is great enough.
That said, any free range bird is in danger from a number of predators...depends on the location.
Best to have a safe coop and run in case you need them.
There are other considerations to letting chickens roam your yard:
Will they stay in the yard?
Will your neighbor tolerate them in their yards?
Will they destroy your gardens?
Will you tolerate them pooping all over your patio, deck, lawn furniture, vehicles, etc?
...just a few things to think about.