For sustainability of livestock I'd look at feed conversion ratios: https://en.wikipedia.org/wiki/Feed_conversion_ratio#Conversion_ratios_for_livestock https://

For sustainability of livestock I'd look at feed conversion ratios: https://en.wikipedia.org/wiki/Feed_conversion_ratio#Conversion_ratios_for_livestock https://en.wikipedia.org/wiki/Feed_conversion_ratio#Conversi... Chicken wins.