I understand a lot of people have trouble free ranging. I have done it successfully for almost a year and a half, morning to night. I realize I may be one of the lucky few. I lost a spangled butcher stag last Christmas to a red tail. My advice is don't have littles when the leaves are off, especially ones that are spotted.
I don't take it for granted, I have a woven wire fence going up around the property. I also have three dogs. My chickens are surrounded by woods and have tons of cover and two large outbuildings to shelter around and under. I witnessed a chicken hawk attack from 6 ft away, but I had heard them alarming and went to check it out. They had cover under my boat overhang on my smaller outbuilding, and my canoe. They get smarter and more aware, and none were harmed. I saw a huge (red shouldered?) hawk the other day out in the woods in a large oak. I hollered at him and he left and didn't return. I truly believe they prefer to hunt their natural prey, and have plenty of it elsewhere in the large fields around here.
I killed a possum the other day that wouldn't stay out of the coop. He seemed mainly interested in the feed and the shelter. I killed a black snake that was circling my lame guinea last year, I got there just in time.
I live in a neighborhood out in the country, and due to several factors things have been working for me. The hawks and other predators have easier places to hunt in the nearby 1000 acre fields. Owls at night are my biggest worry for my 7 game hens that roost in the trees. Cryptic colored birds are the way to go if they roost outside. An owl nearly got one of my SG's that roosted outside on a low roost I had put up for them for during the day. I had to chase them off of it at night, so the roost immediately came down after the incident. I haven't had a problem since.
Coons and foxes don't come around, can't say why, my and other neighboring dogs probably, but I keep my fingers crossed. When I finish my fence I will have 3 dogs with full time supervision of the property. My biggest worry is neighboring dogs, hence the fence. My male has been in a good fight with a neighboring dog, and another tiff the other day. He let's them know to stay well away.