Great Dane was Provoked and Attacked

Question
Our Great Dane is 3 years old and we have had him since he was a 7 months old. He was provoked by a 12 year old that was at my house, the boy kneeled and looked at "Zeus" in his eyes and growled at him, Zeus then attacked the little boy and left many horrible wounds all over his body. Also, in the past year or so Zeus has been growling at my two sons (16&12) whenever they try to correct or forcefully put him in his cage. I also have two girls (8&1-1/2) and I am now fearful that I cant trust him anymore. He has never done anything like this, a side of barking at people and he is NOT neutered. My first reaction is to find him another home, or even worse. Please help me and let me know if this is a sign of things to come or just expected to happened when provoked! HELP!

Answer
Any time a dog exhibits sudden or uncharacteristic aggression, the first thing to do is have a veterinarian check the dog for a medical cause that might have a solution - anything from vision loss, to hypothyroidism, to seizure activity, to abscessed teeth, to arthritis.

The next thing you need is to get him neutered as a lot of aggressive behavior is associated with an intact male dog. He is three, is there a reason that he was not neutered when he turned a year old? If you have a family pet, it is the most responsible choice, also because you have children you should teach them the responsibilities and why it is a good idea to have them spayed or neutered.

Your children should never forcefully put him in the crate, and if I were a dog, I would do the same thing, whether it was towards you or your children. A dog should be taught that going in the crate is a positive event and not a negative one, and this is what your children have created. There is always one leader in every pack, you should not have multiple people correcting him, especially for the same thing. This becomes very confusing for a dog which is why he reacts so negatively.

Part of the responsibility in owning a big dog is to instruct others how to act around your dog. When he attacked the boy, provoked or not, he can never be fully trusted around children again. Furthermore, he should never be left alone with children, ever, not even for a split second. It would be very irresponsible to place a dog like him in another home, as you know he has a bite history. You can and would still be held liable if he were placed and attacked another child.

Each year nearly 2.8 million children are bitten by a dog, and nearly 80% of these are inflicted by intact (not neutered) males.

There may be ways to keep the dog and minimize risk. If you were able to provide your dog with a safe, warm and secure outdoor kennel with plenty of space to run about, a daily long walk and plenty of human attention from you, it may be possible to provide a high quality of life to both your children and the dog. In this situation your dog would never be left with children unattended, or even never come in contact with them. However, if your dog's quality of life would be substantially reduced this is not an option. If you decided to get rid of the dog, the most likely destination is a shelter. Unfortunately, a shelter will not re-home a dog that is a potential danger to people, and therefore the sad but most likely conclusion would be for your dog to be euthanized.

Great references:

"How to Live With Kids and Dogs Without Losing Your Mind" by Coleen Pelar
  
"Raising Puppies and Kids Together" by Pia Sylvani

If you decide AFTER all this is said and done that you do not feel safe with the dog around and there are no signs of anything listed above and all has been checked, you can try to find him a home where he will never come into contact with children (which is highly unlikely), or the best thing at that point would be to take him to the veterinarian and have him euthanized. I personally would not take him to the shelter, because taking a dog in, you are responsible for him till the day he dies, and if that means you are taking him to the vet to do it, he needs to be there with someone that loves him so that he will not be scared and can go peacefully.