That would be good.
Do they free range?
How old are these birds, in months?
What all and how exactly are you feeding?
Might help to clean the poop boards daily, then see who is roosting where, and check first thing in the morning.
Our chickens free range most of the time. They are about 8 months old and we feed them layer pellets. The pellets are usually a different brand every time they run out. We just switched their feed to a different brand (that could be it). They get treats (sometimes) and table scraps. And the chickens like to scratch around in the compost.
I clean the poop boards daily because there is so much manure from our 9 chickens. I suspect that it's one of our Dark Brahmas but I don't know who because they all crowd into the same spot over the poop.
This is what I use when I need to monitor a birds intake and output:
I isolate bird in a wire cage within the coop for a day or two....so I can closely monitor their intake of food and water, crop function(checking at night and in morning before providing more feed), and their poops. Feel their abdomen, from below vent to between legs, for squishy or hard swelling. Check for external parasites or any other abnormalities.
Best to put crate right in coop or run so bird is still 'with' the flock.
I like to use a fold-able wire dog crate (24"L x 18"W x 21"H) with smaller mesh(1x2) on bottom of crate under tray.
Then you can put tray underneath crate to better observe droppings without it being stepped in. If smaller mesh is carefully installed, tray can still be used inside crate.