One of my ferrets chews on the food bowl when he eats. he does it before and after and it is so loud. I guess it don't hurt him but is he ok? He seems happy, bowl movements and urine is good and still so playful. Haven't changed his food or anything.
Your ferret probably needs something to keep it's teeth down. My rabbit did this until I bought her a few wooden toys to chew on. I'm not sure if it's the same for ferrets though.