Great thread Christy!
Pappilon - I agree with Christy. Behaviourally it is far better to desex before they hit this stage. Otherwise you then have a potential habit to break. And territorial marking is a strong natural instinctive behaviour. Hopefully the desexing will reduce that drive.

As for the chain throwing. From memory I think this was originally developed by John Fisher as a distraction technique because of the exact noise it made. The problem with it is that it was then turned by other people into a dominance technique (hence the addition of the 'bah'). It resulted in dogs being actually hit by the chain and dogs losing eyes etc. I agree with what Christy said in that it is now considered generally inappropriate by vet behaviourists. Additionally it is a pretty useless tool in itself. Tools that tend to work very quickly usually do that because they either have a large effect on the dog, or the behaviour itself is very new. Otherwise what you tend to find is that without supportive training in addition to a tool the dog becomes quickly habituated to the tool use.

Just a note - I am not a veterinary behaviourist. I am a wildlife biologist that specialises in animal behaviour. However I worked with domestic animals for a long time (as a vet nurse and in an animal shelter) so can speak with some understanding but techniques and current theories in this field are constantly changing. Which may go some way to explaining why dog owners are often given different opinions by different people. If you see someone for dog training or a dog problem it is important to see someone who is up to date with current knowledge. That is why you may have heard Christy or I talk about going to someone who is accredited by the delta society. But when looking for someone even within this society check to see how often they are upgrading their knowledge. The top of the domestic animal behaviour chain are veterinary behaviourists. They are who you need to see if you have a severe behavioural problem (eg. severe anxiety, aggression). Next I would recommed Delta Society dog trainers who have been trained by vet behaviourist. They are who you see if you have a small behavioural problem or need some training help.

Hope this helps!