When I did rescue (of Rottweilers), one of my first lessons was taking a small Rottie bitch from a shelter, and having her pull me off my feet on a martingale collar. After that I always used a prong from shelter to car and car to my own yard or house. It is, in my opinion, one of those keep dog and handler safe situations. However, I have heard a dog yelp when a prong tightens. No one will convince me they don't work via pain, and most Rotties are not particularly sensitive souls. In the years I did rescue, I'd never heard of no-pull harnesses. My experience was that head halters took conditioning, some dogs never accepted them, and I didn't like them myself.
As to my e-collar experience, when I first began tracking with my dogs, my mentor strongly advised snake-aversive training, so off I went and did it with my older girl, Story. After hearing her scream and seeing her huddle and not only not want to go near the snake but anywhere near the whole area, after seeing her jump back and act afraid of anything strange on the ground for months after that experience, I decided never again. If I lived somewhere where poisonous snakes were a looming and large danger, I might have decided differently, but while there are rattlesnakes in my part of Colorado, I've never seen one on my property. I'd rather take the chance and rush my dog (or self) to an emergency clinic if a bite occurs at the location of most tracking trials here, where the chances of snake encounters are higher, but not IMO high enough to put a dog through that again. You have to ask yourself why the snake training people use electric collars to impress upon dogs that snakes are to be avoided at all costs if an e-collar merely tickles?
So some of this is a personal choice, but when anyone starts telling me how these things don't hurt dogs, I roll my eyes.
What level was the e-collar at? The e-collar shouldn't be a punishment.. if I'm reading this right the dog coming across the snake meant a shock??.. thats.. not right... I don't ever use more than a 3 on my mini educator.
if your dog yelps while on a prong you are doing something seriously wrong. It isn't meant to hurt, just cause discomfort