Would the biomass of the owl pellet be different if it was fresh from the mouth of the owl?

Yes, the biomass of an owl pellet would be different if it were fresh from the mouth of the owl compared to a dried or older pellet. Fresh pellets contain undigested remains of prey, including fur, feathers, and bones, along with moisture. As the pellet dries over time, it loses water weight, resulting in a lower biomass. Therefore, fresh pellets would be heavier and contain more organic material than older, dried pellets.