Actually Jess. It is a bit different with dogs.  You see for the most part our current crop of dogs are bred to do something.. they herd, retrieve, guard, hunt varmints, protect property and flock, and provide companionship.  So my point is that if the need is for a dog to hunt varmints .. get a terrier.. that is what they were bred and developed to do.. need a dog to go in the bush and fetch your bird- get a retriever. Need a dog to protect you and  your stuff... get a guardian.. so the closer you get to the desired traits that you want you can better modify the behavior with training. For instance, if I wanted a dog to retrieve my birds I would not use a chihuahua or a Neapolitan Mastiff.  Can you train them to do that - yes - but that is not what they were bred for and if the Chi gets eaten by a snake and the Neo eats your bird .. you can't blame them..