I've been waiting a solid week for mine to eat a butternut squash, it's pretty hard but i roughed it up for them and still absolutely no takers. Maybe it's because i gave it to them and they didn't just snatch it.
Mine WILL eat pumpkin and squash raw, but prefer them cooked.
My father grows a large number of butternut squash, and after cutting up a few (or if he has to cull a few that have bad spots) he'll cook up the peels, seeds, and "innards" on his wood stove (too cheap to pay to run the stove he says) and brings it by for the chickens. They love it!