Protein levels in commercial pet foods

Whilst our food is raw and mostly chicken &
bones, the protein levels in kibble and cans can be a misnomer, due to
the way proximate analysis is performed, being a percentage of
nitrogen in the food.
Whilst our food is over 77% raw meat and no grains, this works out at 16%
protein, the protein levels in kibble and canned dog foods, are not
just from meats, they include protein from grains (mostly soy & corn),
and from indigestible animal parts i.e. feathers & horns etc