Find a trainer ... "I have a dog that is "now" aggressive with kids" but I don't have kids of my own can you help me??? Yesss ... good luck with "finding a trainer" for that one! Most of the "traditional trainers" "can't help you!" So if you see "Positive" only, or "Gentle" "anything" don't bother, waste of time, money and effort they can't help you!
If you want to actually find a trainer that can help you?? The only one that I am aware of that "routinely" deals with "Aggressive Dogs" and "Kids" is Jeff Gellman:
Solid K9 Training aggressive dog rehab, dog anxiety - Rehabilitation and Family Dog Training
I have heard him say that he can help people find a "Balanced Trainer" local to them. So I'd contact him, if you want to "find a trainer" thast can actually help you, if no one here has a local recommendation for you?? And ... dogs and kids ... looks like this:
And I did read the "Leerburgh" approach to kids (pack members and it was with babies) and it seemed kinda "insane to me??" But it involved the "scent" of the babies and the dog being "corrected" for going near that scent! That stuck me as kinda crazy ... but he's the expert. Not much help for you in any case ... just stuff I know.
There are things you can do to help your dog "Make Better Choice" but in as much as he has already "apparently" lunged at your niece??? That tells you all you need to know! This dog should not be allowed near toddlers period! "Put the Dog Away" if you have "toddlers over" ... put the dog away end of.... discussion! Toddlers as a rule "Don't" make good choices! I "Don't" screw around with kids and dogs!
That said ... "Crap Happens!" And the best preparation for the unexpected ... is a well trained dog! Rocky (OS WL GSD with Ataxai) ... is by and large pretty boring these days.
But ... back in the day ... he was a "Monster!" My first true "Red Zone" dog! And he was a "Wobblers" doggy so any kind of DDC, or Yank and Crank options ... were "off" the table! I had to find other means???
Aside from "Rank Drive issues" which are not your problem ... he had "people issues" he did not much care for uh anyone! And using "extreme" caution I discovered that "included" toddlers!
The kiddie sequel would set him off and beyond that ... when I tried again ... using extreme caution ... to let a kid touch him ... he grabbed my hand instead of being able to bite the toddler and let go! When he realized he had me?? He let go ... OK that did not work! So ... I was part my there being around kids was fine. "Place" was OK but "toddlers" laying hands on hit ... a bit to much ... noted!
OK fine so what I did was to teach him how I expect him to behave around "people" and apparently a "by product of that" was that he learned to make "good choices!" As I am want to say ... "crap happens" and the best "preparation for the unexpected ... is a well trained dog!
http://www.germanshepherds.com/forum/8015033-post3.html
And in as much as I have found "no one" other than "Jeff," that deals with the "Kids and Dogs thing??? I would suggest that people that "don't" have kids ... at the risk of looking liking some kind of "creep" practice "Place and Sit on the Dog" around areas where kids hang out. Usually the kids will be safely "contained behind a 6 foot chain length fence. Your dogs job ... with "Place or Sit on the Dog" is to do "Nothing!"
And Place and Sit on the Dog ... are here:
Fearful, Anxious or Flat Crazy "The Place CommanD - Boxer Forum : Boxer Breed Dog Forums
My two cents ... KISS.
Guess I have to add ... a few weeks ago, I did kinda sorta reluctantly let a older child pet him. I was kinda freaked when the kid reached out with both hands and grabbed him by the head!!!
Rocky ... was like "No big deal." :laugh2: