Can slurry be agitated twice?

No extra nutrients but a second agitation would break t up even more and it would be a faster acting slurry as opposed to poorly agitated lumps of dung taking all summer to break down

Hard to know what is a Ballpark figure. If the draw is near then roughly €3-400/bay

Little if any nutrients lost I'd imagine, all that's escaping is the toxic gases at each mix, the p and k should be almost 100 percent still there.

Me and plenty others are like you this year, mixing same tanks, extra times, as slurry is going on little and often.

Was some direction of 60 euro cash an hour with my local man, I'm sure that's a minimum though.

We don't spread anything else but later on in the Summer I'd top it before moving the cattle out and they hoover up the toppings. The field that was spread would be closed for about three weeks to let the grass grow before they would be turned back into it. I suppose it's like paddock grazing but slightly less intensive.

True but a lot of farmers want a fixed price. I'm only guessing at that price of €3-400 per bay including agitation as there are too many unknowns such as depth of tank, width of slats etc

You’d be better off turning down the work from a farmer that wants a fixed price per bay for agitating and spreading slurry. There’d be only one reason for that question and that is that the farmer is trying to screw the contractor.

I’d take pleasure in laughing at a farmer that would ask that and walking away from him!