Most zap collars for dogs warn that they may not like the zap and may turn on their owner. Also to use the lowest zap charge that will get the dog to do what you want it to, and some dogs just aren't going to take to a zap collar as a means of controlling their behavior.
We used to use them, but once one of our kids didn't fasten the collar properly and I came upon a bunch of computer electronics like stuff sticking up from the lawn and immediately realized the dog ate the collar because she could!
We later went to the Invisible fence routine, and it has worked well with both our dogs for many years.
And some dogs may change the way they behave independent of a collar or not, It is their nature, as it is ours as humans to be unpredictable and to expect anything, because anything can and often does happen. Most often when we least expect it. Remember dogs may be domesticated as breeds, but too many breeders breed for certain highly regarded traits and this can lead to other 'Frankensteinish' like negative outcomes on the down side of over breeding.
Dogs are obviously territorial, and have pack mentality, and Alpha dog characteristics in their collective DNA, over millions of years on this, and possibly other planets.
I recommend being aware of what you have, beware of how you keep your dogs in proximity to each other and especially how you feed them. Our younger lab, purebred started attaching our other older lad for her food after she gulped down her own. I had to separate them via out french door into our mudroom, to allow them to eat at the same time but not getting into it over their food.
A friend had several dogs in their outdoor pen, and one day came home to one having attacked and killed another for no particular reason the owner could discern.
Things happen, and with an animal as capable as a dog to reek havoc, the outcome is not always good.
So, like buyer beware, dog owners beware too, were talking about animals here, and they can be unpredictable, so be cautious, and think about what animals can and will do if they choose to do so.
Beware, be prepared. Good luck.