I would say yes. Chickens seem to know what they need. We feed an all-flock formula that does not contain calcium, and our laying hens help themselves to oyster shell as they need it. Non-laying birds (old, young, male) don't partake.
What a great question! My 2-yo Black Australorps had a very hard molt this year. One in particular I called Hurricane Hannah, poor thing. We switched them (gradually) to Feather Fixer from All-Flock as soon as they started going into molt, but they don't seem crazy about it. I have noticed a lot...