Yesterday I noticed bloody poop in my 4 week old chicks living space. I hadn't noticed it before and it seemed to progress and get a lot worse by the end of the day. None of the chicks seemed lethargic and they were all eating and drinking. I borrowed some corid from a friend and treated the flock, watching them until about 3am and I saw a lot less bloody droppings and a lot more normal.. However, the corid is expired, but I figured it was better than nothing since the store was not open so late. This morning I noticed a mix of normal droppings, but also several bloody as well, and I was wondering how long it usually takes to eliminate the bloody droppings after treatment.. The corid expired August 28 2015, so should I run to tractor supply and get some new or another medication ? I've never had this happen with any of my chickens over the years and am terribly worried, so please let me know!