I have always wondered if there simply just isn't research being done on the subject of testing hormone levels in working dogs. Would you be able or willing to do a short video helping people understand how to create some kind of testing program guidelines that could be applied to any kind of working dog, regardless of job? I've been trying to take the information in your videos and apply some concepts to what I am actually in the process of looking for, which will be a service dog for my disability. The "wash out" or fail rate is very high in most cases and dogs, my first dog failed because I bought a working line German Shepherd with every single dog in a five generation pedigree - excluding his parents, again, I was new to trying to find a dog on my own - and he was just not right for the job. Too watchful of his surroundings, a service dog needs to tune that out to focus on their person. Etc, etc. It's a challenge because I'll be putting stock in a puppy rather than a proven trained service dog, because those cost around 10,000 dollars or more. I hope this made sense, I've just been trying to figure out the steps towards finding dogs for the job.
Blood samples would have to be taken while the dog is working to really begin to understand what’s going on in the working dog. I don’t really see much reason for that, given our understandings of hormones when it comes to solving your concern of puppy selection.
JMO I would say bonding with the pup would be inportant. If dog is bonded to you where they are always focused on you for your service needs. Exposing a pup early on to other distractions and making sure his focus is on you. Would also depend on what needs you have for the dog. Seeing eye dogs need to be aware of surroundings and make decisions to protect the person. A clear understanding of what you need and expect from the dog would probably be the first thing I would look at. Then train accordingly. Just my opinion.