Vegetarians eat milk or eggs?

Do vegetarians eat milk or eggs? Or things made with them like breads and cookies? Or do most look for vegetarian recipes? I am going to have company that is vegetarian and I would like to know. Also I am aware of the nasty process made in getting milk and the way hens can be treated. I am not vegetarian but am very careful what I eat. So if not, if you have your own free range chickens that are not given antibiotics and you get milk from a local farm that doesn't use hormones/antibiotics treat cows or calves badly and you could enter and see personally that its what you want it to be, would that change what you would eat? Or is it really just because it comes from an animal?