So,
this is about feeding eggs to chickens (yolk, yolk and white, yolk, white, and shell) - linking the whole thread, so you can follow along and check the math if desired.
And this is copied from another post, regarding Layer feed.
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"Layer Feed" has been scientifically formulated to meet the MINIMUM dietary needs of commercial hybrid laying breeds, under commercial management practice, during their commercially productive lifespan (about 18-20 months +/-, typically). It is a low protein (because protein is expensive), high calcium (to support prolific egg laying) formulation intended for RSL, BSL, and similar hybrid layers sharing the following characteristics:
1) Early Onset of Lay
2) Large eggs relative to body size
3) High Frequency of Lay
All that calcium comes at a cost, however. Excess calcium builds up in a chicken, contributing to kidney damage as well as damage to other organs, which is likely, but not guaranteed, to affect lifespan and quality of life. As with any situation where "the dosage is the poison", the length of time before the excess calcium intake is balanced by egg production, as well as the amount of calcium intake daily have an effect, as does variations within individual chickens. Its like smoking - no individual cigarette is guaranteed to give you cancer, but its a statistical certainty that the more you smoke, and the longer you smoke, the more likely you are to develop a cancer attributed to your smoking.
Excess calcium is bad for ALL birds. It is worst for Roosters, who never develop a way to excrete extra calcium - they never lay eggs, their kidneys become increasingly damaged with time. They can also develop gout, intestinal problems, lesions, renal failure, etc. Its also bad for pullets before start of lay - and if your pullets are Dark Brahma, or another breed that goes six or seven months before start of lay (rather than the 4-5 months for commercial breeders like Golden Comets) that a long time for calcium to accumulate. If your hens don't drop eggs almost every day (most don't), again, calcium will begin to accumulate, at risk to long term health.
The flip side, is a shortage of protein. Protein is expensive, which is why the bare minimum appears in Layer feed. But protein is very important for the development of new birds, particularly the first 12-18 weeks. Protein assists weight gain, muscle and feather development (which is why many - myself included - recommend higher protein feeds during molting even for those raising nothing but laying age commercial egg producers who plan to keep their hens thru their first molt - factory layers become dog food, etc around that point, often as not). Birds which don't get enough protein will try and eat more, increasing their calcium uptake... Certain breeds need a lot of protein, either due to large body size, heavy feathering (winter hardy breeds), or an "excess" of attractive, but not necessarily practical, feathering.
Unlike calcium, "too much" protein is not a danger to your birds (unless you have ducks, then protein over 24% is associated with higher incidence of "Angel Wing"). Indeed, it generally benefits them in better overall form/body condition, increased early weight gain, and lessened duration and apparent severity of molting. So it really comes down to expense. Typically, the cost of an all flock or flock raiser blend is $1.50 to $2 more than a similar layer feed from the same product line and manufacturer per 40# or 50# bag. Free choice oyster shell, so that your active layers can get as much as they feel they need, but not more, will likely add $7-10 a year for typical backyard flock sizes. One small bag.
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