I have 3 day old Redstars, two week old Bo's, and nearly 3 week old RIR's and I can testify that they all love crumbled up microwave popcorn. It's exceedingly funny watching them grab a chunk and go running for the corner while being chased by the others. The sad part is, there's a pile of it...
Chickens don't chew their food in their teeth, and so, nature has given them a sack (crop) in their lower throat(alimentary tract) in which the food passes. The grit being heavy rest in that sack, they move the sack around and the stone grit helps break down the food they eat. I hear they...