Welcome to BYC. That is very sad about your first flock, but I am glad you are staying positive and taking steps to ensure it won't happen again. I wish you the best of luck with your future flock!
I'm so sorry to hear about your losses. It's such a shame that dogs are about the number one killer of chickens... if people would only take responsibility and train them or actually keep them locked up! I wish you luck with your new flock and new dog, but not all dogs make great protectors, even if they grow up together. Sounds like a nice pretty assortment of chickens you've got coming. Best wishes!
Welcome to BYC, and good luck with your new flock. I hope that you contacted local animal control and the dog owners after your last loss. It's good to be on record in case these dogs return. The electric fencing should be a good deterrent. Good luck.