Animal Welfare Professionals

I have adopted a Pyrenean Mastiff (I didn't even know this was a separate breed) from a private party who did not socialize or train the dog.  I have had her for two months.  She is already spayed, and about 12 months old now.  The reason the previous "owner" re-homed the dog was because the husband was somewhat disabled and could not handle the dog.  I have experience with German Shepherds and 100 lb Labs, but I am frustrated with trying to train this dog.  I live rural, and my property is fenced on three sides, but one side is open, so I cannot leave her loose for fear she could run into the street (speed limit 55 mph).  She still has tremendous puppy energy.  I have a fenced in kennel that is 60ft x 40ft, but it is not large enough for her to get a full bore run going.  I know she will calm down as she gets a little older, but I was wondering if anyone had any tips on getting the attention of a pretty stubborn/willful dog.  I have her on a short lead when I walk her around the property.  I keep treats in my pocket and give them to her when she is obedient.  I have taught her to sit, stay, come on command, but all on leash.  We are working on down.  She thinks down is when she is supposed to roll on her back and play.  She is a sweet dog, but she definitely has issues with wanting to pull away when she sees another dog (she wants to play).  I am looking for a fully fenced dog park, but I am afraid she may knock someone over.   This is a photo of Scooter  (with my husband) at ten months of age.  Any suggestions?

You could try more enrichment for mental stimulation, like puzzle feeders/toys.  There is a fantastic group on Facebook that has TONS of ideas and people asking questions similar to yours:  https://www.facebook.com/groups/canineenrichment/  A lot of the ideas are homemade and easy.

If you can afford it, taking her to doggy day care once or twice a week would give her the opportunity to play with other dogs her size. Maybe contact local shelters or trainers to see if they know of any playgroups that meet in a fenced area. I know that's not super helpful but finding her a buddy with a fenced yard could make a difference. Good luck!