I've raised plenty of kids...some not even my own...and grandkids, aka "critters" in my house. If she can't keep track of them, then she apparently needs to put up a fence for her "critters". What if they had run out in the street and got hit? Would you also blame the driver that hit them? Same difference. If she doesn't take responsibility for her children, then she is stupid one.
As for the dog, I blame the owner as well, not the dog.
I had 5 children in 6 1/2 years and Yes, once in a while one would go out without me knowing it...I lived on a court and at one time or another, some neighbor would be out looking for the 4 year old....
I commend you on your great parenting....../s
I just love the blame the victim people and not the killer or attacker.