Couple of questions

Question
QUESTION: I have a couple of questions for you and I hope you can help.
1. My mom has 3 dogs and because she works all day, training has been left to me. All three dogs are over a year old (the oldest is 3 and the youngest is 2). I have been trying unsuccessfully to train them not to jump up. All three have this problem and seem to feed off eachother's energy when someone comes in the door.
2. I also want to train the same three dogs not to bark so much (they bark at everything! Someone on the otherside of the street causes them to bark!) but have no idea how to go about doing that.
3. The oldest dog is also the newest dog. We adopted him from the Humane Society back in December and has recently started showing signs of aggression to one the other dogs. How would I go about training this out of him?

ANSWER: Megan, you'll need to work with one dog at a time to establish good responses to basic cues individually before expecting them to respond in a group.  

1.  You're absolutely right.  They feed off each other's energy when someone comes to the door.  Teach each dog what you expect him to do when someone comes in the door - sit, chase a toy, touch your hand with their nose, etc.  All these things are incompatible with jumping up.  Train whatever it is you want them to do and practice with few distractions.  Once they are good with YOU coming in a door, add another family member into the picture.  Watch this video for tips:  http://www.youtube.com/watch?v=lC_OKgQFgzw

2.  Block visual access so they aren't constantly watching for passersby.  Here's a good article on teaching dogs to quiet on cue:  http://www.siriuspup.com/pop_barking.html

3.  What triggers the aggression? What exactly is the new dog doing that you describe as aggression?  Have there been fights with injuries?  Is he guarding things?  Is he growling or snapping?

Let me know about #3 and I'll try to give you some suggestions.

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QUESTION: I haven't seen the aggression myself but my mom says she saw him bite one of the other dogs to establish dominance or something like that. There was no blood and the other dog was fine (he's quite the chicken so he immediately hid behind my mom)

Answer
Dogs rarely bite to establish dominance.  They sort out their pack position with body posturing and species-specific signals that they use to communicate with each other.  If you can determine what triggers the aggression (like a specific toy or bone), try and set up the environment so there's less chance of it happening again.  Allow your 'established' dog to have free time away from the newcomer whenever necessary.  If there is constant bullying going on, you might want to re-consider keeping the newest dog unless you're committed to spending a lot of time training and managing the household.  If you need a referral to a trainer in your area, please let me know.