[bainsfather]

I have learned something new today (re manure from dovecotes).

However, I think this is another example of something that is 'just too small to matter' in terms of feeding the world's population today. Often I see 'nice' stories about e.g. using human waste to fertilise fields, that quite frankly do not (usually) scale at all well. We (UK) use tractors to shovel and spread manure - 10s, 100s of tons of the stuff - a dovecote or 10 really isn't going to help, and certainly won't be economic.

It seems a bit like someone telling me I should use an abacus to increase my compute power - 'they were a good idea in the past, why aren't you using them now?'