I adopted a 1 and 1/2 year old male miniature Schnauser from the Humane Society last week. He has had two homes in which he was not successful due to some aggressive behaviors. He is usually very lovable, but when my adult son comes downstairs he growls and barks at him, without cause. I was napping on the couch yesterday with my dog and my son came to cover me up with the blanket and Pepper went wild. Snarling, lunging and barking. It scared us both. I would appreciate any suggestions.
First technique: Schnauzers are very protective of the people they love. Have your son "adopt" him as his own for awhile. Let him walk and feed him and teach him tricks. This is the best cure if it works. You must have very little to do with him and don't let him sit with you during this time. You son has to be the predominant one until your dog sees he has two owners. This doesn not prevent aggression to others outside of the family. It sounds like everyone has backed off from this dog, not dealt with the problem.
Before you do this second method, I want both of you to become more of the pack leaders. You are to eat first with him waiting until you are done before you feed him. He must "lay down" before you feed him. You must make him stay when you go out the door FIRST before a walk.
Schnauzers take a little while to learn something, but when they do, they never forget so you are now teaching this dog to unlearn a bad habit and relearn a new good habit.
2 POP tecnique: If this doesn't work then "set" him up so you can correct him. The correction has to come from you. Sit in a way that is easy for you to move freely. Have your son walk over to cover you. As soon as the dog even looks aggressive (watch his eyes, you will see a change in his look) take your fist and turn it sideways, not like a fist, but like a gavel with your thumb up, bring this up under his chin quickly (before he can even see you do it) and kind of "pop" his jaw shut while you yell NO! and get up and hover over him saying "NO". If you are careful not to let him see the "pop" he will not associate it with you personally, but will have a consequence that to him, just comes out of the air to shut his mouth. DO NOT PUNCH him. That is not what I want you to do. I want you to hit his jaw only hard enough to close his mouth with a snap. This is for biting, with you saying "NO" and shutting his mouth at the same time he will start to realize the NO/NO Bite, means to shut his mouth. If you only yell, he won't know which thing he is doing wrong. Dogs need to learn something one at a time and while they are thinking about it. If he shows any aggression like growling before you son comes anywhere near you then use this process at the onset of the look before the growl.
You will need to repeat this whole thing immediately and maybe for several times until he finally stops the aggression.
If after all this training, there is no improvement there is another pretty sure cure and that is an anti anxiety/aggressive drug that a vet can give you. It could be a tranquilizer/ or prozac etc. It usually does a good job after it builds up in his system. He will be a little
fuzzy for a couple of weeks until his body adjusts, then he will be fine. I know many dogs on this, 90 percent calm down significantly.
hang in there, schnauzers are great dogs.