When we still had our chickens (yes, they're gone now, I'll tell that harrowing tale another day) I would often remark, usually audibly, about how incredible it was that our chickens would go around the yard eating weeds and bugs and turn those things into an easily stored package full of ideal protein, vitamin D and omega 3's all of which are in forms which I can easily digest and utilize.
Yes, I too could be eating weeds and bugs, but even if I ate proportionately the same amount that the chickens ate, I wouldn't be able to get the same nutritionally benefit from them than I can by eating an egg from pastured chickens. Our bodies simply are not as efficient at digesting plant matter as other animals are. Thanks be to God though that these animals are incredibly efficient at turning various foods (some of which it would actually be harmful for humans to eat) into nutrient dense, easily digestible foods such as eggs, milk and meat.
That being said, as with all truisms anymore, the case is better made via a meme with an endearing picture, so enjoy: