I recently paid to have a dog cremated, and now I have a question about the process?

I recently paid $100 bucks to have my brother in laws’ deceased dog cremated, and when I got the ashes back, I noticed that they were about the same amount as the ashes from a cremated human. (yes, I’ve looked inside funeral urns). Do you think they cremate each dead animal individually, or do they do several at a time, and simply separate the resulting ash into several equal piles? Surely a 60 – 70 lb. dog wouldn’t create as much ash as a 185 lb. person?

I know a few details about the process of human cremation, (including which bones do not get burned completely and have to be ground up). I wonder if it is the same for pets, is it done individually or do they simply incinerate a bunch of dead pets at once?