I'm probably gonna get 'bashed' by other trainers for saying this but in good concience -I have to.
I would not recomend using an E-collar for child aggression.
Some dogs are very sensitive to it and act very strangely weeks or even months after the training has ended successfully. I really believe that down the road, some dogs would only remember that children = pain and behave even worse than before.
In my early years as a dog trainer I "healed" dog aggression in a very stable male GSD using an e-collar. The GSD was soon impeccable around other dogs (wouldn't even look at them but was not afraid) and impeccable in most every other respect too. 3 months after the e-collar he ran and attacked a young Rotweiller that was far away and just smelling a bush.
The attack (by this incredibly obedient GSD) was so quick, unprovoked and vicious that I could only blame it on "E-collar trauma". Can you imagine if the Rottie was a child?
I have since used other methods for dog-aggression with complete success.
I even cured the GSD who turned out to be an amazing dog that learned to PLAY with other adult males. Other methods can take awhile longer than the e-collar but they are rock-solid.
I have witnessed other mistakes (with e-collars)by other trainers but I don't want to bore you.
E-collars do wonders for some situations but not ALL situations and not ALL dogs.
We should not just try to take the easy way out -we may really screw up our dogs in the process.
Btw. Too many bad trainers screwing up dogs with e-collars has caused many countries (including Germany) to ban the use of e-collars for ANY purpose.
I often work on child-agression as a private trainer. I even have 3 children that I pay to help me in my work. They are 5, 6, and 8 and very "dog-wise" and immensely helpful.
I work the dog in obedience next to the children at first in a controlled environment, then get a friendship going with them in the dogs home and then go to parks and playgrounds and practice with the owner doing most of the handling.
I use a choke chain or prong -depending on the dog.
The sad thing is that for many dogs that have had a bad experience with a child at a very young age, there can never be a full recovery. They will never LIKE kids. Some dogs dislike children so much that they can only be tought to ignore them. They cannot be trusted off lead around them, ever. E-collar users would argue that with their method the dog learns to ignore children even if off lead and I would cheer right along with them if it wasn't for the aforementioned risk. The e-collar teaches some (smarter and tougher) dogs to just be faster and meaner when the time comes to attack. To get the bite in before that damn shock comes. They know the shock is comming but they grin and bear it because they GOT THAT KID GOOD! and the bite was worth the shock. Now the kid will "go away" and there will be NO MORE shocks. Needless to say the bite is ALWAYS worse after the shock training because the dog wants to get his "PAIN-worth".
Other, more sensitive dogs, could see a child and be 'reminded' of the shock and actually 'feel' it even though there is no shock! These dogs could freeze in terror or run away upon seeing a child.
And this too could occur like a fluke, months down the road, when you lest expect it. For the 'meanies' you could have them 'collared' for life but even then you must always be on the alert.
If you shock a dog WHILE its actually biting a child there is a 50-50 chance the dog will think the kids fighting back and bite HARDER. Am I scaring you? Good.
Cause I'm gonna get 'bashed' for this and I wanna get my 'Bashings-worth'.
In the end it is your choice. And I wouldn't be a bit surprised if you were successful in fixing the problem with the e-collar. I'm just saying I woulndn't risk it because there are better ways. Ways that don't have any side-effects.
Of course the best thing is to 'prevent' the problem before it happens. And it easy if you take children around puppies as seriously as you should.
I feel it is incredibly important for owners of new puppies to practically "live in fear" of children and to protect their pup from bad experiences that could literally ruin their future dog.
I have socialised many puppies about town and have stopped children from doing something nasty to a pup more times than I can remember.
It really helps to tell the annoying child this: (their parents aren't ever there for some odd reason!):
"Please don't scare my puppy! He's never met a child before and I would hate for him to think they are all mean like you!"
Good Luck in whatever you choose to do, I honestly only mean to help out.
Dogs are not our whole life, but they make our lives whole.
--Roger Caras