This mystery plant popped up where my father-in-law empties his chicken's cage. I tried to look for ingredients in the chicken feed as a clue, but that wasn't very useful. I've spent lots of time trying to figure out what this plant is, and I can't seem to get much help. My father-in-law kept saying it was corn when it very first started cropping up, but I'm from Indiana, so I knew better, heh.

Thanks in advance!

Here is a link that might be useful: {{gwi:305833}}