I'm new to keeping chickens. We just got 10 fairly young hens. I have a question about the feed. The feed I use is rough ground corn. But this feed has a lot of "corn dust" in it. I would say half of the ground corn in the feed bag is ground very fine, like powder. How do I tell when I need to change the feed? The chickens eat the bigger pieces first. Then my feeder is full of "corn dust." Will the hens eat some or all of that along with the larger ground corn? Or do I simply need to throw away any feed that is in a powder state. I am curious because if I throw away all the powdered corn in the feeder I will waste have the contents of the feed bag. I hope this question is clear. Thanks!