http://www.concordma.gov/pages/ConcordMA_TownClerk/dog
You are totally within your rights. I would assume that "under control of its owner" means that the owner must lift a finger or voice to control the dog successfully.
Section 1. No owner of a dog shall permit such dog to be outside the confines of the property of the owner unless the dog is held firmly on a leash or is under the control of its owner.
Section 2. No owner of a dog shall permit such dog:
a. to disturb the peace or quiet of any neighborhood or endanger the safety of any person, by biting, barking, howling, or in any other manner;
b. to run at large or unmuzzled in violation of an order of the Selectmen or the Dog Officer;
c. to worry, kill, maim or otherwise injure another’s fowl, livestock or domesticated animal;
d. to chase a vehicle on any way open to the public travel;
Frends know gud humors when dey is hear it. ~ Da Crockydiles of ZZE.