Dan Barber is a celebrated chef. He has been raising voice about increasing levels of chemicals in the food and how we are veering away from nature.
In the talk, Dan mentions how chicken waste (entrails, beak / feathers / feet etc) are pulped and fed to fish. Feed animal entrails to cows led to outbreak of BSE or Mad Cow Disease.
A British inquiry into BSE concluded that the epidemic was caused by cattle, who are normally herbivores, being fed the remains of other cattle in the form of meat and bone meal (MBM), which caused the infectious agent to spread