As my new rabbit was discovering my room today when I put him back into his cage/play area he made a grunting noise when I let him back out he stopped. What could this mean?
Many bunnies will grunt if you're doing something they don't like. Other bunnies will grunt if they're trying to be romantic toward you. It sounds to me like your bunny was grunting because he didn't like you putting him back in his cage.
Finley grunts too sometimes. Her grunts don't always mean the same thing though. Sometimes it's because she's excited (at food time), and other times it's to tell us to slow down and let her get comfy before we snuggle her.