For the most part only dogs. The coop is next to the house and I am always home to keep an eye on things. I had a problem with a fox last June when I couldn't put up the chickens at night. Our old set up collapsed in a huge storm. In the early morning hours any chicken that would wander the edge of the property would get taken. Once we rebuilt then we haven't had any issues except for a loose dog last week.
Predator losses are always the big issue with free ranging chickens vs. keeping them in enclosed runs. There will almost always be some losses in free ranging, and it's up to the chicken owner to determine whether or not those losses are acceptable enough for the benefits of free ranging. I'm glad it's working out for you.