you would be surprised how sneaky dogs are...
I had a miniature schnauzer, about 90% blind. she could make out shadows sometimes.... and about 50% deaf.... she was on her last limb and one night my mom took her outside to do her business, and my mom turned around or something..whatever the story is... And my dog was gone.
She was outside, in the middle of october in michigan for 7 full days. At three am on the 7th day, someone knocks on our door and is holding the dog... he said he found her crossing the road less than 1 mile from our house...
So the dog could've been right outside the house, or miles away...never know... hopefully you get to keep her, but hoping even more the proper owners get to reclaim her.