Chickens and cows should not be eating grains. They should feed on their natural diet. The problem is intensive farming.

Do you think it’s possible to feed 7 billion mouth without intensive farming? How much space do you require to relocate over 70 billion land animals who are slaughtered every year to a free-range farm, as you say?

Proper farms treat their animals well

Do you think anyone’s slaughter / murder could be called a good treatment?

they could utilise land for animal grazing, land that cannot be farmed for crops

How many animals such land can support in your assessment? And do you know over-grazing is the cause of forest destruction? Forest can never regrow on lands being used for grazing.

Digestion of meat is much easier and far more efficient (and nutritious) than plant matter.

Meat is harder to digest. Ever wondered, why meat is heavier on digestive system than veg? How long is it before you feel hungry after devouring meat compared to after eating veg? And nutritious!!! About 90% of the antibiotics being consumed in USA are consumed by farmed animals. Growth hormones, steroid, various artificial supplements and GMO food is part of their regular diet. Their residual component in meat is major cause of serious diseases. And whatever nutrients are there, they aren’t in the bio-available form. Animal food is highly acidic. Our intestine is 3-4 times longer than carnivores, so in the long 48 hours of digestive path, you would only have rotten meat in your body.

Meat has zero fiber whereas plants have zero cholesterol. Make your own choice!

whether the human can assimilate that is another matter.

I don’t think any proof is required for this statement with millions of people thriving on plant-based diet for centuries. All your statements are but fallacies. You may be aware that even WHO is in favour of the adoption of a vegan diet.

When you talk about coprophagous animals like Gorilla and the bacteria processing in the body, it’s a true that all digestion is breaking down of food and is accomplished through the help of billions of microbes in our body. The only problem was with Vitamin B-12 which is produced in lower part and cannot be easily observed by our intestines. So coprophagy could solve this problem for some. But if you keep your body healthy with a balanced and healthy diet, many colonies of bacteria can develop and it has been reported that B-12 can be absorbed by the intrinsic factor as it is required in very minuscule amount. Today what you get from animals is too fed them through supplements and is not natural. So concerned people can directly supplement it, if needed.

BTW, good to know that you know aliens better than the most! You are probably an exception in this case 😊.