Or, to put another way, a weak nerved dog is a dog that is naturally skittish and generates an exaggerated response from a non threatening situation. This could mean a dog that will use its fight or flight instinct in situations that are not necessary.
I am unfortunately seeing a lot more of these types of dogs...in every breed. People are not making sound choices when it comes to the temperament of the dogs they are producing. They look at specific things they want to breed for and even a dog with a really weak temperament, if they show these certain characteristics, will be bred. I even see this in the working breeders at times, who will ignore a dog with a really crappy temperament because he works stock well.
People, there are plenty of nice working border collies...instead of breeding your fearful dog, go find a solid tempered dog that is nice on stock instead.
There are many excuses breeders will use for the weak tempered puppies they are producing. One of my favorites of ALL TIME are the fear periods. Puppy buyers are often told their puppy is going through a fear period, it is "normal" etc. etc. which is used to cover up the fact that their puppy might have a weak/fearful temperament.
YES, I do believe in fear periods...they are real and serve a good purpose in the development of a puppy and young dog. HOWEVER...I see this being used as an excuse for poor temperament when the breeder is not picking dogs with good temperaments to breed to.
I prefer to call these periods "sensitive periods"...being wary of new things, things out of place, etc. It is NOT CHRONIC and it NOT fearfulness. Using fear periods tends to make it seem like every puppy goes through their puppy hood scared of things, even in the most normal of environments...which should NOT be the case.
A puppies response to novel things in it's environment SHOULD go like this:
Puppy is startled by the novel object
Puppy investigates the object to see if it is something benign or to be feared
Puppy accepts the object as something into it's environment
Puppy recognizes future encounters as NON-THREATENING.
A puppy should be able to bounce back. Plain and simple.
Weak nerved dogs see everything as novel...they can't (or it takes them a LONG time) to include something into their "safe environment"...regardless of whether the object is a threat or not.
Now...this is taking into account that the puppy has not had a traumatic experience (aka getting mauled by a large dog, a gunshot at point blank range next to it etc etc). Or is not socialized and some dogs by breed are naturally more standoffish...one must take that into consideration.
If your puppy is chronically fearful of things, that should be a HUGE red flag for you. And not something that should be written off as a "fear period". If your 8 week old puppy comes home and is worried about lets say your doorbell, and after a few times hearing the doorbell is STILL scared of the doorbell...my mind would put up a red flag. A strong tempered puppy would maybe startle a bit the first or second time (if they even noticed it!)...but after that will dismiss it as a normal part of his or her environment since it is not going to hurt them. THAT IS NORMAL--even a sensitive period to novel things with the ability to bounce back is NORMAL. Chronic fear is NOT. Regardless of what the breeder says.
Socializing a puppy should be FUN! Puppies are naturally very curious and confident and enjoy life and seeing what all it has to hold! Puppy hood should NOT be a solid year or two of "desensitization". That is just not a solid tempered puppy.
And lets say this dog, when it turns 3 years old, is a good dog, can deal with life and has no real issues...should we then BREED this dog!?! My opinion is NO. SOMETHING is not right about the genetic makeup of the dog...breeding is to better the breed...not HOPE the bad temperament isn't passed on.
I know many people that feel that is how raising a puppy is! The breeders of their dogs have completely convinced them that a fearful puppy is how all puppies are! NO...I completely disagree.
I have raised several puppies and I have only had ONE pup that was weak nerved and wasn't able to deal with life. I no longer have this pup and it made me realize that I needed to be better at picking a solid tempered dog.
The rest of my puppies have all grown up without times of chronic fear...on occasion one will have a sensitive period...but in reality I have only had 2 that have ever even done that. And it is just when they seem to be a little more aware of their surroundings...that is ALL, no extreme flight or fight response (fear biting), extreme reactivity, no urination/defecation/anal gland issues or the inability to bounce back from being startled. Other than with the one weak nerved pup (which everything I had to do this with it seemed), I have NEVER desensitized a puppy to something.
The solid tempered puppies just LIVE life, enjoy life and are not fearful...it really is that simple :)
And yet, there are many people who I see on a regular basis who are desensitizing their puppies to all sorts of things that in reality shouldn't even be an issue in a puppy with a solid temperament. Many of these people are even new to dog training, which makes it a thousand times worse! If you realize you have a puppy like this, PLEASE get some help from a behaviorist or dog trainer in your area.
These dogs are later regarded as "shy" or "protective" when in reality the signs were there from the start with these dogs. Weak nerved dogs need a LOT of training on impulse control and how to properly react to a fearful stimulus. However these types of dogs will always have issues to some degree, and will need to be managed.
Please when you are looking at puppies, know the temperaments of the sire and dam and MEET them if at all possible. They should be friendly and act like a happy, normal dog. Confident and sure of themselves. Not cowering, running away, anxious, tail tucked, or standoffish. Because then you are not starting with a clean slate on your puppy but rather weak nerves and a fearful temperament.