defending my territory!

I hear my dogs barking middle of the day! Hmm. They bark but not usually in the day. I sit a second then decide to look outside. Out the back door I see a German Shepherd wandering around our back yard...Not even giving it a second thought or a what if he is a mean dog, just thinking my chickens are back there, I go flying out the door yelling and hollering "GET OUT OF HERE...GO GO GO! As I run onto the back porch, Blackie, our chicken who refuses to be penned, runs out from under the porch just a squaking and hollering. Midnight comes running after the dog and the dog meanders off, Midnight following it till it leaves, me all the while yelling at it and chasing it off. Then I think, what if he was not a nice dog, but then again if you saw what he saw you'd probably leave too, mean or not.