My twins (boy and girl) will turn 11 in early July and my wife and I have decided to get them a dog for their birthday. We're leaning heavily toward a Golden Retriever. That's what the kids have asked for and my brother had one for years and he was a great dog. Some friends have a Chocolate Lab, which also seems like a real nice dog. He's been to a training school and behaves well. He almost never barks. Whatever we get, he/she will be an outside dog. I'll buy or build a nice insulated house. I plan to use an electronic perimeter fence. I don't want to put a dog in a pen or use a chain, I think a dog should have the freedom to run. We have 6 acres and I'll probably fence in about 3 acres.

The down side of the Golden Retriever is the size. I'd prefer a smaller dog, partly because we like to travel and a large dog would be harder to travel with. Are there smaller varieties of Golden Retrievers, or are they all the same?

Also, what about training a dog not to bark at night and when we're not home? So many people have dogs that bark a lot at night and bark a lot when their owners are not home, so can a dog be trained not to do that?

I read somewhere on the internet that Golden Retrievers are not good guard dogs due to their gentle nature. Is that true? If someone were to take aggressive action toward one of the kids, what would a Golden Retriever do?

PS: What do I need to consider when choosing male or female? Whatever we get, it will be spade/neutered.