I agree with kt, if your chooks are on the lottie site, the dogs should be banned, and the owner should pay for new chooks. If it's your neighbour at home then things might not be so simple. If he uses those dogs for hunting then surely they should be kept away from other animals and children all the time?
It sounds like you have pretty good security for your chooks, unless you went another foot underground, I don't see what else you can do to protect them. I remember on tales from river cottage Hugh FW built a crazy chook house on stilts and chooks had to be taught to climb fox proof ladder. Seem to remember they learned quite quickly. I'll have a look on t'internet for it. :) Emmy