30 pounds at 7 months is pretty petite. I wouldn't think that large breed biscuits are necessary. As far as how long an EB grows, I don't know, but there are several EB owners here who can probably help you with that.
:hello2: Welcome to the board! I can't wait to see some pics of your girl!
:hello2: Welcome to the board! I can't wait to see some pics of your girl!