Hi everyone. I have four small adult dogs. One of my dogs, the youngest, at 7 years, is quite a loner. She seems to become more & more so as time goes by. She absolutely adores me!! That's not the problem. But she will spend most of her time outside away from the other dogs inside. They have a doggie door, so they can go in & out at any time. She's not playing or doing anything out there. She just doesn't seem to want to be in. She comes in when it's time to eat or time to go to bed. She sleeps with me & the other dogs in the bed at night. I guess it's just her personality, but sometimes it worries me. Any thoughts?