[TollingSteady]

> In consequence, I need to buy less and thus emissions can be reduced.

You're not taking into account that, by virtue of being an animal taking in oxygen and creating carbon dioxide / other pollutants, the chicken itself is contributing to greenhouse gas emissions.

The question is, in real life, are the bonus calories we get from animal farming efficient enough so as to be worth those greenhouse gases? Given the massive GHG emissions of animal agriculture, it doesn't seem so.

Perhaps I'm misunderstanding your example, though: feedback appreciated