I have two 3 year old miniature dachshunds that are very fun and loving. I did some training when they were pups but nothing major and nothing recently. They both run to the back door barking at nothing, when they go outside they will bark at a wall. Neither of them like other dogs (probably due to the fact that I didn't socialize them when they were young) but the smallest one will lower herself to the ground and do a high pitched bark if a dog comes up and sniffs her butt. I'm doing basic training with them right now and have seen minor progress. Any tips on fixing these problems? can I train both dogs at the same time or must they be separate? When I train them separate the dog inside the house barks out of jealousy. Thanks in advance