English Bulldogs

We have a dog named Dozer that was purchased when he was 2 years old. We have had Dozer for 8 months. Dozer came from a farm where he ran loose without much supervision. He was not let
into the house and left in a garage when he wasn't running loose
with cattle, etc. Our understanding there was a period where there were other a few other related bulldogs and he was the youngest and only one left and the people didn't have enough time for him as they both worked so they sold him to us.
At first he wandered the house and couldn't settle down. It was hard to get him into the house and he would continue to try to go out to the garage.
Potty training eventually improved. He was doing fine until about a month ago when he got into something in a wastebasket, a piece of food and when we went to take it away he growled and snarled and ran. We freaked out as we had never seen him or any other dog act like this and started chasing him and screaming at him to drop it. It had a piece of plastic wrap around it and we were afraid he would choke or swallow and then become an obstruction.
Since then there have been about four other episodes where something he's gotten that he shouldn't have like a pencil falls to the floor he will snarl and growl like he would bite us if we took it away.
Since the first incident we have become calmer. We have tried the spray bottle which sort of works. My neighbor said to do the alpha roll, I think it's called, where you lay them down on their side and hold them till they submit and calm down.
Following these episodes we ignore him and he seems like he wants to "make up" but each time it gets handled a little differently. We're not sure what to do and we don't want it to escalate till he does bite us.
Other than that we have no problem with feeding and taking food dishes away or bathing him or walking him in a harness. He seems fine. Just the territorial thing with the objects.
Also there was an instance where my husband was trying to wipe feces that stuck on his butt and he didn't like that and growled. His butt does seem a little sensitive and he's ok with very gentle
wiping.
Pls reply. Thank you
sheryl

We have a female bully, (bought her at 2 weeks, brought her home at 6 weeks), that will growl like she is going to bite over her toys. But she is really saying, play with me now. She will bring a toy and place it in your lap without letting it go. Then she will growl like she is going to eat you up. But she don't, she just wants to play.