I have been raising show poultry for years and have also been a 4H leader.
As far as your own pets go, put the dogs on a leash and see how they do with the chickens. We have never had a problem with any of our dogs, they are trained to know that the chickens are part of our "pack". Cats are just never a problem, the chickens will kick their heinies. When free ranging, hawks and eagles can be a problem if you don't have a rooster to look after your hens (the rooster will keep watch and give a signal for his gals to hide if he sees a large predator). But a few hours out and about in your yard should be fine, especially if your home to keep an eye on them.
A previous poster mentioned neighborhood dogs being a problem. Here's my hard and fast rule on that: If my chickens are on your property and your dog attacks them, it's my fault.
If my chickens are in MY yard and your dog attacks them, I follow the rule of the THREE S's....shoot, shovel and shut up. I don't know why your dog ran away from home, but I sure haven't seen it!
Keep them locked up tight as soon as the sun sets. Raccoons have very nimble fingers, make sure locks are raccoon proof. I even have rabbit hutch wire under the floor of the coop to keep our rats which will chew through the floor.
I love my chickens, I have several that are over 10 years old. They're no longer layers but they are our pets.
the best web site I've found for advice is
www.poultryconnection.com
Good Luck!!