You might want to suggest consulting a second vet. Ask about feeding scratch instead of layer feed to prevent laying eggs and see what they say. Assuming the second vet actually knows anything about chickens, their answer will help to convince your boss.
Wow. Just wow...
That is some of the absolute worst, most harmful, ignorant advice I've ever heard. And from a "professional"????? Damn.
Scratch is low nutrition (lacking in protein, vitamins, minerals, fats), but high in energy (calories). It is not good for overall health, but fine as a...