Given that manure is manure, then surely if it is organic or not makes little difference?
When you consider how much manure you may put on your land once it has rotted down, then surely any traces of additives from non-organic farming practices are neither here nor there?
So it begs the question other than salving your conscience why bother paying any extra for organic manure?
I suppose it is up to the individual, for me it matters not if it is organic as the practice for me of following NO DIG and not using any other additives other than those that are considered to be organic.
Avoiding where possible the use of chemicals for outways the cost of organic or not as far as manure is concerned.
Aside from which I have no control of where the manure that comes to our allotment site comes from, so the point is mute.