I'd say that you don't need to make it all at once because my heaps get up to 70°C+ and they're filled as and when material is available, but you probably do need a reasonable volume of fresh material at the same time and a good mix of "green" (nitrogen-providing) and "brown" (carbon-providing) materials to get it to work. When we have a lot of grass clippings for example, I layer it fairly thinly with cardboard or waste paper which stops it turning into a sloppy stinking mess and it breaks down nicely. Keeping all the materials in small pieces is helpful too. When my father-in-law turns up with a pile of tangled stalks and suchlike from his flower beds, I drag them all into a long line on the grass and run the mower over them, then put the contents of the collector into the compost.
I'd guess that with manure taken from paddocks (which I think would count as "green") you'd need more "brown" than when it is already mixed with wood shavings. I might even be tempted to add a little water if it has dried out.
Generally though, having had a few, I think the "dalek" composters are a bit rubbish. I'd be more tempted to get four pallets, wire them together in a square, line the sides with cardboard and use that as a compost heap. Ideally put some sort of cover over the top to help keep the rain off and the heat in. You can possibly go a bit smaller if necessary, but I reckon 3'x3' is a reasonable minimum. Certainly with the mix of waste that we tend to have.
James