Hi Jim
Her behaviour isn’t abnormal. By that I mean that some dogs want to stay home and some like to wander. It’s just a part of an individual dog’s characteristics. It could relate to her earlier upbringing in that perhaps she was left on her own and the opportunity was there for her to escape. But that may be an oversimplification….it may just be a part of her nature.
However it needs to be said that entire dogs (particularly entire males but also entire females) tend to wander more than neutered dogs. Again this can vary dog to dog. If you intend having her spayed there may be some “improvement” in her behaviour.
More important with this is the fact that she has the ability to escape! You need to establish a good barrier. When she’s in season her desire to go out and seek a male dog will be even greater and of course male dogs will also seek her out. If she can get out then they can get in!
I hope I’ve been of help but please feel free to contact me back if I can assist further or if you have something more to add.
Kindest regards, XXXXX (also a Lab owner)
Dog Veterinarian
Bachelor of Veterinary Science (University of Melbourne, Australia)