Deegan is our 2 yr old beagle/jack russell, neutered. We've had him since he was 5 months old. His "discipline" consists mainly of wearing his muzzle for about 5 minutes, which he absolutely hates -- we're not sure why but it works well.
If he hates his muzzle, it's probably because you didn't understand how to properly acclimate him to wearing one. A muzzle should not be perceived as punishment by the dog, just as "clothing". This link could prove helpful if you want to re-train him to like the muzzle: http://bcrescuetexas.org/Training/ATM_Desensitization_muzzle.pdf
He gets his muzzle when he steals our other dog's food, steals our food, gets into the garbage, or barks uncontrollably.
You might have more success if you manage his environment more appropriately. Don't let him "practice" behavior you don't like. Feed the dogs separately. Keep your garbage in a secure place, and grab a copy of "The Bark Stops Here" (dogwise.com) Don't engage in yelling at him to stop barking - that's just a duet (and you got a Beagle/JRT why LOL?). Instead, try clicker training - reward him once he stops barking on his own. Have a look at this: http://www.clickertraining.com/node/1125
He definitely exhibits alpha behavior, normally playing with the biggest of the big dogs at the dog park and sometimes picks on smaller dogs or "weaker" dogs if given the chance. He does however give in to our other dog Mandy, a spayed mini dachschund/beagle mix, even though she is smaller and calmer than him. He lets her win mostly when they rough house.
It sounds like he is pretty normal, except for any bullying of other dogs, which you should discourage. Many leader dogs are calm, like Mandy. So, I am not surprised that he would give in to her.
His first display of aggression I can remember was one time he was in trouble, don't remember for what, several months back. I went to reach for him to put his muzzle on and he bolted upstairs. When I reached for him a second time he beared his teeth at me, growled, and barked at me. It was something I'd never seen him do to me and though he's only 22 lbs, it made me pull back. I didn't know what to do so I told him "no" and put him in his crate for a time out.
"No" means very little to dogs. I think Gina is right in her assessment that your dog is defending himself against you placing the hated muzzle on, which you have done repeatedly as punishment, rather than as a simple way to keep him and others safe. I disagree that your dog is "alpha". I think he's just a dog that has no idea what is expected of him, so has taken matters in to his own paws.
More recently, we just moved in to a new house a little over a week ago. Last week when the cable guy came out Deegan barked at him like he usually does when a stranger comes in. It didn't seem like an aggressive act, just Deegan's normal loud barking. The guy put down his hand to say hello. Deegan would normally be fine with this, he's very curiuos and friendly, but not this time! He bit his hand. I can kind of see why this happened though since you would never stick you hand in a much bigger dog's face but it still surprised me though because Deegan has never behaved this way.
You said he is two. He is now an adult. While he might have responded differently as a pup, he may have perceived this guy looming over him as a threat, and responded by telling him to get lost. Not appropriate, but understandable. Many dogs do things they would never have done before after a move. For example, it's common for dogs to forget their housetraining skills in a new location.
Over the weekend we were all sitting on the couch watching tv, myself, my boyfriend, and our 2 dogs and cuddling for quite some time. When Brian got up for a second and came back, Deegan was in his way so he told him "down." Deegan didn't budge and Brian repeated, "down!" When Deegan still didn't move, Brian reached out to pick him and move him but when he did, Deegan bit his hand. Again, not being sure what to do, we put him in his crate in a quiet, dark room for a time out.
You need to change the dynamic in your home and start thinking "benevolent leadership", & NILIF, rather than punishment. Have him wear a drag line (leash) in the house, and when he is somewhere you don't want him to be, gently coax him off, but then reward him for doing as you ask.
I am a little concerned about Deegan's behavior. I know he's an alpha and we try to keep him in line by doing things such as making him wait to enter a door behind us, he's not allowed on our bed, he must sit and stay before he gets his food, etc. He's been through obedience school too. I am not sure why he's starting to bite though but I really want to stop this immediately. He's always been very sweet and the friendliest dog. What is the cause for this behavior and if he does bite someone what do we do afterward to make him know that this is not okay behavior
Don't wait until he bites someone!!! If you are concerned enough to ask that question, invest the money in a qualified behaviorist to help you with some protocols to alter the behavior you don't like. This is where to find one: http://www.animalbehavior.org/
Dogs can guard space, just as they guard food:
http://ahimsadogtraining.com/blog/articles/resource-guarding/
Regional Director for Massachusetts, International Positive Dog Training Association
Director, SeniorCare Pawsitive Connections Program
AKC CGC Evaluator #3669
Therapy Dogs, Inc. Tester/Observer
Sioux, CGC, TDInc.
Maska, CGC, TDInc.
Sequoyah, CGC
Fergie, Retired Lap Dog, Age 19
Dancer, CGC, TDInc. (1989-2006) #1 Heart Dog
"If you talk to the animals they will talk with you and you will know each other. If you do not talk to them you will not know them and what you do not know, you will fear. What one fears, one destroys." - Chief Dan George
"The fidelity of a dog is a precious gift demanding no less binding moral responsibilities than the friendship of a human being. The bond with a true dog is as lasting as the ties of this earth can ever be." ~ Konrad Lorenz