My 19 month old Sheltie, Lady, in the last couple weeks hasn't wanted to go on her daily walk around our neighborhood anymore. We on average for the last couple months have walked 4-5 days a week, for about 30 minutes. She needs the exercise as she is overweight, and honestly, it's not bad for me to get it either. The last few times I have tried to take her though, she will get a little ways down the road, then stop and sit and refuse to move. She will turn and look back at the house and want to head back. The one day I did get her to go around when we started off the walk in the opposite direction around the neighborhood. That too, she now doesn't want anything to do with. She has started to slow down during the day, like she still plays, but overall lies down and sleeps more, just in general slowing down in her activity as she gets older, though she's not old. I want her to be more active as she needs to be. She walked just on a regular leash, and did fine, but I am wondering if maybe I should try a Gentle Leader thinking it may be better for her if she starts pulling? She has had a couple issues with walks. We stop everytime a car goes by, as she likes to herd them. Also, maybe a month or so ago, a dog got out of it's front yard (even though they had a sign up stating they had an invisible fence?) and ran right out into the street (almost getting hit, the owner ran right behind it) over to her, which I know scared her, even though the dog was smaller than her (pug). This same dog in question does back and forth laps in it's front yard whenever it's out and always barks nonstop when we walk by. I don't know what to do, she needs activity. Any suggestions? Thanks for any help!