It's going to be nearly impossible to feed Joycie regular feed and the rest FF. I'm not sure I see why FF should cause her to stop laying. It's purely coincidental with no other supporting evidence.
The seeds are probably from the FF which has BOSS and scratch grain mixed in with the flock grower.
So, is the consensus that she may have an infection that is causing her to stop laying as well as the weird poop and lack of appetite? Should I start her on a ten day regimen of amoxycilin?
it is my experience that if a bird stops laying in the middle of laying season if possible i would separate her from the flock, make sure she has grit, start her on electrolytes and worm her. then check her over for mites, peeling skin, feather loss and feel her crop is it hard and huge or is it soft and empty? Lastly check her eye's, comb and waddles are they the same color and size? are they pale or discolored?