I do withhold feed, well grab them off roost at night and cage with only water, then slaughter first thing in the morning-so they are not starved per se but have pretty much empty intestines, last minute meal of scratch to fill crop for easier removal....so gizzard was also pretty much empty except for some grit and that stick, gizzard was malformed, from stick or not <shrugs> who knows. I imagine ingesting the indigestible would have less affect on older birds than youngsters.