Most layer feed (in the US) is around 16% protein and 4-5% calcium.
So switching to a higher protein (18-22%) lower calcium feed (starter, grower, flock raiser, all flock, etc) still with the oyster shell (side consumption will go up as needed by active layers when not included with food) and...
Welcome to BYC! :frow
Boy, aging sure does change things.. including muscle size and strength. :hmm
Please describe your usual feed routine including treats and supplements in order to be able to make any relevant suggestions.
Have you ever had fecal floats done to check for internal...