Brown is excellent in pretty much all departments, especially the larger more popular ones such as biology, psych, history, English, etc. So I definitely wouldn’t cross it off your list for that worry. Brown has incredible resources, professors, and research (it is an Ivy League after all!), and I’ve heard biology is a popular major.
Check out this post for more info:
http://talk.collegeconfidential.com/brown-university/792875-browns-strong-majors.html