If you cut out the concentrates, James, have the goats got access to a mineral block? Some of my male castrated goats never have any concentrates, but I always make sure they have a mineral block in their shed. The goat mix has vitamins and minerals already mixed in, so if we are cutting that out, it does need to be replaced somehow.
Pygmy goats do not need a vast amount of food - wish my big Billy goat was pygmy sized. He has an enormous appetite!!!