I had a small flock of chickens a few years back, but had to give them away due to asthma problems. The problems are resolved now, though, and I'd like to get more chickens, because they were a lot of fun. I had a flock of 6 mixed gold sex and red sex links, and they got along very well with our dogs, and we never had any problems with predators. Now, though, I have larger dogs, and there has been a recent increase in skunks/possums/etc in our neighborhood. What breeds would be able to fend for themselves fairly well against predators? I obviously plan to keep them in a secure coop overnight and keep an eye on them during the day, and our dogs will be slowly introduced and trained firmly that they do not mess with the chickens. Still, just in case a dog's instincts kick in or a possum wanders by, are there any breeds that can defend themselves and would still be friendly to humans and not overly aggressive? Are there any breeds I should avoid?