Things my dog does

My brother found my dog a number of years ago abandoned outside his old school. She followed him home and ever since she has stayed with us.

When we first had her she was very suspicious of other people and afraid of everything and anyone. My mums old mate who has had dogs all his life said he reckoned she was beaten and then abandoned by her last owners.

Its not really an issue that bothers me, because she has always done this but I'd like to know why if anyone knows anything about this type of behaviour. She is very protective of me personally. If anyone shouts at me etc she will start showing their teeth telling them to back off.

Whenever we are eating dinner for example she will immediately run into the back hall and lie down there. Whenever I give her a treat or any food for example she will never eat it in front of me, but rather she will run into the back hall. She brings everything into the back hall pretty much - all her food etc.

If I'm walking into the back hall when she's eating she'll stop and wait until I leave before continuing. Is this behaviour normal?