IIRC, ginger is okay is very small amounts for chickens. It's a very potent herb! I'd probably hold off on feeding ginger to chicks until they're older. But I'm no expert, that's just my gut feeling about it.
The pulp is also now mostly fiber and not a whole lot of nutrition, so go easy on it. I've read that too much fiber can upset chickens' digestion. If you ferment their feed, it would be a useful thing to add small quantities of the pulp to. I'd say keep the pulp at 5% or less of the same portion of feed or fermented feed. Or just give them as a treat, free choice and see if they like it. If you do add it to the fermented feed, the fermentation process will improve what little nutrition is still left in the pulp.