Hello. I have a 10 month old now who is about 60lbs. At 8 months old he started what I thought was being aggressive. I got a trainer that was recommended by other people with bullies. She told me he is acting out and trying to be dominant. He was a very well rounded pup manners wise. Then at 8 months it all went out the door. I would be sitting and he would just come up and bite us and start pulling on us, attacking ankles when we were walking, getting up in our face and barking, the list goes on. We had to take him back to puppy basics. Treat for everything positive. We now make our kids carry treats in their pockets that way at any given time if we see positive behavior we can treat it. If we start to see negative behavior we can redirect him. Any time he would get aggressive with treats, toys, items laying around the house We grab the scruff of his neck and put him down on the ground. We had to show him we are the boss. When he would jump at our hands for treats or toys we would knee him off or push him away with our hands. That would only make him more aggressive. Now anytime he gets aggressive we barely get our hands on him and he is going to the ground by himself. You will need to have someone show you when he is ready to be let up. We thought we had the hang of it and then he would just go right back to it once we let him up. You really have to learn to watch their body language that way you can learn to let him up when he is ready. We have had to hold him down for up to 10 minutes depending on his mood.
We first went to petco and wasted money. I really suggest you get a trainer that is familiar with bulldogs or large dominant breeds. It really has made a huge difference.
Another major thing that has helped is hand feeding him both meals everyday. He is learning that you are in control of his food and will learn to not be aggressive to the hand that feeds him. We also attached him to us when we are home it teaches him to watch you and being by your side is a good thing. We do not have toys laying around for him to have access to. Before we give him a toys, treat, food, etc we make him work for it by making him do sits, downs, turn in circles, etc. Good luck. It is very frustrating but if you are able to get a good trainer it will be well worth it.
Also exercising him is a must. We take our pup on 3 walks a day.
You've been given great advice and suggestions already, I don't have any experience with aggression, but agree with the others with getting a trainer. I hope you are able to find a solution to his aggression. Please keep us posted on how he is doing, and if you found any solutions. Good luck. Sending you love, hugs and prayers.
LEARN A LESSON FROM YOUR DOG, NO MATTER WHAT LIFE BRINGS YOU, KICK SOME GRASS OVER THAT AND MOVE ON.