How long to puppy fer periods last. I know ther are times when fear periods are recognised but do they come to an end after a couple of weeks or do dogs carry on being more wary of things?

It is impossible to generalised but pup are into everything up to about 10 weeks and they seem to start to become wary between then and 12 weeks. After 12 weeks it is important to introduce new things with care unless they have already learned to trust you, and you should have no problems, old dogs can not only learn new tricks they can accept new experiences providing they have never been scared witless.

I'm not sure I agree 100 % with all the advice given in this article, but for the sake of reading about different stages, it's interesting: http://www.vanerp.net/ilse/GSDINFO/stagesofcaninedev.htm Having a very difficult breed that makes split second decisions and can take years to change their minds, I always say I wish mine were born 2 years old as that is when they finally start to feel more confident about things. :)

The article regarding the behavioural stages of puppy development is a good guide, but only a guide. Some pups skip some of the stages and some go through some twice. Each pup should be treated as an individual in his/her own right and any fear or difficult stage should be downplayed as much as possible.