In organic systems, manure should be composted.

According to the NOP (§205.203(c)), raw manure must be composted unless:

- Applied to land used for a crop not intended for human consumption;

Œ- Incorporated into the soil not less than 120 days prior to the harvest of a product whose edible portion has direct contact with the soil surface or soil particles;

or

Œ- Incorporated into the soil not less than 90 days prior to the harvest of a product whose edible portion does not have direct contact with the soil surface or soil particles.

Edit - There’s much more to the compost standards. For more info, see here:

https://www.ams.usda.gov/sites/default/files/media/Manure%20...

Bird droppings & phosphate were in such high demand that entire islands like Naru were strip mined for it up into the early 1900's. Haber/Bosch did not kick off until 1909 leading to manufactured fertilizer.

Also death from starvation is a pretty serious health risk.

Using human waste (night-soil) in the fields was a common practice in England, Japan, India, and elsewhere for centuries.

I was talking about this with one of the farmers from my CSA. They sell eggs as well as produce. She told me, "I'd love to let the chickens loose in the fields," partly because of the fertilizer, and partly because they eat bugs that eat crops. But apparently this is forbidden because of the disease risk.

There are also other scary health risks in that region:

https://www.bbc.com/news/world-europe-11711136