Protection of animals and public

My son was walking home from school and there was a chain link( the standard with the holes) with the white strands budded up to the sidewalk( totally legal) but still close enough for a dog to reach its mouth THROUGH THE FENCING and grab my boys sweater,it PULLED his arm INTO the fencing HE DID NOT STICK HIS FINGERS IN WILLINGLY there was witnesses and bit his finger bloody,he is older so he managed to get his hand away with no real damage but I was shocked to hear from animal control about how it was the dogs property so there is nothing illegal, and they would let them know but that was it I'm not looking to press charges or have the dogs put down I just wanted it prevented from happening again,I even offered to buy and put up a screen along the fence line I dunno what else to,I had my fencing set back to be respectful of passersby and I think we could all benefit even just a few inches off the sidewalk.