I tutored reading and there were some kids who read w/ no expression. One thing I did with them is to have them read like "newscasters". I would practice this separately from the other reading skills. Take a short passage, maybe just 3-4 sentences and explain what a newscaster is, and how they speak with a lot of expression to get people to listen. Read the passage like a newscaster while she follows along. Then have her read with you, telling her to match her voice to yours. Then have her try it alone.
I think it would be "normal" for a kid to not read with expression if they are reading for a long time. If she is able to read silently to herself let her do that unless you are specifically trying to teach her to read certain words and to read with expression. I find that even with myself if I read aloud too long I start reading in a kind of monotone after a while. It's too hard to to read with expression for a long period of time.
I also think passages with a lot of dialogue work well. My DS in first grade actually speaks in a kind of monotone and since he reads fluently, his speech therapists have used books with a lot of dialogue and reading aloud to try to teach him to speak with proper expression and prosody.
