Wasteful of what, though?

If a particular farm can produce 1000 kg of meat and 500kg of bones/other waste in a year by raising female meat chickens, would it be a waste to devote that farm to raising 500 kg of meat and 400 kg of bones from male egg chickens? In a sense, that's a waste of the farm to produce half as much meat as it can produce through killing chicks.

It's a philosophical difference on what weight to assign to the lives of chicks, adult chickens, other resources including human labor, etc. The lazy shortcut is to maximize return on dollar investment with no regard for any of those moral, ethical, and philosophical considerations, and that's what most of the industry does today, but even if you shift to a new moral framework you'll need to decide how to weight those things.