- Chicken Starter/Grower feeds generally have 18-22% protein and 0.5-0.8% calcium(low end for pullets to help prevent premature laying, and 22% for broilers & turkey finisher)
- Layer rations have about 16% protein and 3.5% calcium
- Adult maintenance/off-season breeder formulas have only 12-14% protein and 0.5% Calcium. (Birds in molt could use more protein as feathers are mostly protein.)
- Many other species need higher protein as chicks. (some are around 30% ie game-bird starter)
If in doubt or with a mixed flock of layers and non layers with fresh food access(pasture) use the grower formula, and put out a separate dish of crushed oyster shells for the birds to eat free-choice. Do the same if they are almost old enough to lay, birds of all types build up a special egg-laying calcium reserve in the weeks just before they start laying. Green leafy plants actually contain quite a bit of calcium. (In a good balance with some other minerals like Mg and phosphorus and a fair amount of protein. ie. One cup of cooked bok-choy has more usable calcium than a cup of milk.(and no saturated fat)
I have two laying and 5 approaching lay with lots of 'pasture' still in their run, so I have started mixing in 1/4-1/3layer feed with 2/3-3/4 grower and putting out a dish of oyster shell.(Organic pride and Purina as that's what they had in stock.)