That is a pity your manure is so lumpy and it needs breaking up. Certainly one cannot plant into big lumps.
So yes pick out the big bits of wood, then you need to break it up somehow.
I use a manure fork when spreading, to break the manure (which is 18-24 months old and compost really) into pieces no larger than an apple. Spreading it in autumn gives weather the chance to break it up more – what I put on before the Christmas frosts is now soft and crumbly.
