Hair is evidently not digestible by cats which is why they cough up hair balls??? However some organisms can apparently digest hair such as birds of prey and maybe bass or foxes who eat mice? Birds and some predators can digest bird feathers but fish can't normally digest feathers until the feathers are first processed???
I have found a mass of hair and bones hocked up by an owl. I don't think hair can be digested.
I don't know about feathers.
