Even if there were no clumps or noticeable smell, I would still get rid of it. $13 for a new bag of feed is a lot cheaper than losing your flock. Many years ago I bought a bag of cracked corn. The chickens only slightly picked at it. The turkey wouldn't eat it. The horses turned their noses up to it. The wild birds wouldn't eat it. It didn't smell bad. It looked normal. Those animals detected something I didn't.