Aggressive Behavior in male boxer pup

Question
I have a european boxer I purchased from a breeder 5 months ago. At the time, my wife wanted a big boxer as a guard dog and family pet. We chose the largest pup of the litter. At the time, the breeder cautioned us that even at 8-10 weeks of age, he was showing specific alpha characteristics with his littermates and she cautioned us to keep an eye on him and monitor his behavior closely. Shortly after we got him, we had a trainer come in as a consultant. She also warned us that we would need to be especially careful with him as she also noticed his alpha tendencies. In our family, we have 5 kids. The smallest is a 5 year old girl. The pup has shown a little aggression at times, mainly when protecting a bone or food. This has been dealt with on the spot. By and large, he is a good, fun loving pup, though he tends to routinely show a lot of aggression toward other male dogs and assumes a stalking stance when he encounters them on walks. This has been hard to control and we have to keep him on a leash while walking him. About a month ago, my mother in law was taking care of him and allowed my 5 yo daughter to take his food to him outside his crate. No one witnessed what happened, but my daughter came away quite upset with a small puncture wound on her cheek. More recently, my wife gave him a lamb bone which he was chewing, and our 16 year old boy went to take it from him in order to put it in his crate so he could chew it in there. I heard snarling and growling from the garage! When I came upstairs, I went to take it from him, and he growled at me! This was immediately corrected, and by the end, I was able to take it from him without and untoward behavior. Last week, my 5 yo daughter was playing with him. He had been vaccinated that day and may not have been feeling well, but he reared around and struck my daughter with his muzzle. She was left with a red mark on her face, but no puncture. Again, though my wife was in the room, she didn't see exactly what happened. The pup is 65 lbs at 7 months of age, so he's going to be a big dog. My wife spoke to the trainer by phone today. Her thoughts thus far is that the dog should be muzzled when he's around our little girl, which practically, is all the time. She's coming over this weekend to spend some time with the dog and see what she thinks. We're considering getting rid of the dog but will see what the trainers advice is. Although my wife really loves this dog, we don't want our daughter bitten, disfigured or afraid of dogs. Any advice?  

Answer
First, Boxers are not "guard dogs" as a Doberman,or Rottweiler is. They might be territorial, and they might alert you- but, Boxers are people dogs and big, ol' lovable cuddle bugs.

It is quite common for the largest litter mate to be the alpha-- he was the strongest to survive in uteri (in the womb) and has a natural instinct of a surviver, as the weak don't make it in the wild. Domestic dogs are no different- only the strong survive.

ALWAYS keep a dog leashed when walking them- ALWAYS. Do you want to be liable for him injuring someone else, or get injured himself? Isn't there leash laws where you live for God's sake?

Well, someone did not socialize him at an early age- meaning the breeder and then you and your family.

Also, too many cooks in the kitchen... too many people... too many variables.... the dog can't help but take charge himself because he has no direction. No boundaries. Only correction once he has crossed imaginary boundaries that he is not aware of- only you are.

I highly suggest that you re-home him to a household without children and people that are willing to work with him and train him and be consistent.

You are suppose to be the alpha-- not him.

I can give you tips and tricks on establishing the alpha position and modify his behavior and thinking- but I do not know if you are willing to be disciplined enough to do it.

It should have been established at the age of 4 weeks old. You got him at the age 8-10 weeks old as you mentioned, and you should have began training and boundaries then.

You failed to mention how you "correct" him. This is most important and a key element.

So give me information and if you are going to be dedicated to modifying his attitude and behavior-- I will help.

To say the least