Dogs that defend their property from a stray claiming control of said property are as justified as doing so as any Freeper who defends his or her property from any other criminal.
In my opinion, the Freepers would still be justified if, during a scuffle, the fight crossed off their property onto a vacant field.
The dogs were under control until they were provoked. There is no evidence to indicate that the owner was deliberately ignoring the dogs; with two young children, she may have had duties to them that were more important than seeing what her dogs were doing. No doubt, she had heard them growl and bark at that stray before, and she seems to have assumed that the matter could wait while she took care of other business.
Since there is no indication that either of the dogs had ever previously broken its chain, it stands to reason that the owner assumed (albeit falsely) that the chain was strong enough to keep the dog on the property.
While the dogs were, apparently, off the owner’s property when shot, their handling was a matter for animal control or for catch poles, if they truly had not been able to separate the dogs by any other method.
Fine the owner, if you must; shooting the dogs is overkill.
At the risk of appearing to undermine constitutional property rights, counselor, may I make so bold as to suggest that dogs haven't any?
Furthermore, although many Freepers cannot type all that well, I would resist placing them in the same sentence with your canine property owners. Although the former might well benefit from your representation, I doubt the latter would.
In my opinion, the Freepers would still be justified if, during a scuffle, the fight crossed off their property onto a vacant field.
Would a dog following your doctrine of hot pursuit be considered a hot dog?