I have a blue merle collie and he is a lovely dog around the family but if anyone visits he barks like mad and there is no stopping him,he fixates and it is impossible to distract him. If anyone goes to touch him or if he even sees their hands he lunges at them showing his teeth. He has always been easily frightened but he seems be getting nasty rather than better. Please help as I don't ever want him to bite anyone or us!
I would try leashing him when guests are expected to arrive, make him sit back and away from the door (like 5-6' away).
Open the door when guests arrive and only allow him to greet them when he is calm and seated and after everyone in the house has greeted the guest first. Try to make it clear to your guests that he is in training and that they are to ignore him until he is calm and seated, then they can call him over to them for some pets
This is probably easier practiced if you ask some friends to help you out with it a few times within a week, so progress is made faster.
If biting is a genuine concern, I would consider a muzzle (and muzzle training) for practicing meeting guests until he is presenting the correct behaviour.
Allowing him to greet visitors first makes him dominant leader in the pack, and he feels the need to protect his territory (barking is a warning, the next steps are growling and biting...).
Another thing that may help is taking him for a long walk or play session just prior to guests arriving, this will tire him out somewhat and may make him more malleable to your commands and corrections.
Alpha training is also very important. Here are some important points on alpha training provided by the folks of Kingdom of Pets:
1) If you come across your dog while he is sleeping or lying on the floor then you can reinforce your position as alpha dog by making him move away from where you want to go, no the other way around.
2) Make sure that you always go through doorways first. Try reinforcing your position as alpha dog is to walk your dog around the house on the leash, making your dog wait while you walk through doorways first.
3) At mealtimes make sure that your dog or dogs eat after all of the humans have.
4) When your dog wants to go outside for a walk, make it sit and wait until you are ready to go.
I've also found it extremely effective, if the dog is not allowed on couches, beds or any furniture that humans use. Our dog is also not allowed to be near the dining table during dinners, she usually sleeps on her bed or in an adjoining room where she can see us.
It's amazing how much alpha dog training works, our dog Blue is so much more attentive to our commands, and often looks to us for direction when she wants to be active (whereas before it would go to destruction/chasing the cat/whining).
Now if only alpha dog training would "cure" separation anxiety...
