will this work?
ETA: yes!
You have a sheltie!!! 
I was raised with shelties.
No, no, not like that! My mom bred and showed them. 
I love our sheltie very much… but… did you ever get them to stop barking quite so much?
Yes, you just have to train them like any thing else you want them to do. Reward them for doing the right thing (not barking), and punish them for doing the wrong thing. The reward part is crucial.
Now, what you WON’T ever stop them doing is herding the back yard.
While you’re on Flickr, you should visit: