The original question, I thought was a simple one, "Is 16% or 22% better for layers?"
Is there no short answer to this? I'm not sure I have spent much time thinking about this. My chickens free range and eat so many bugs and greens that I really didn't think I had to worry about anything.
The short answer is that it probably doesn’t matter the way you are managing yours. Since you let them free range you don’t have a lot of control over it anyway, they do. The quality of the forage will have an effect but they are balancing it out. Now the long answer.
People get so hung up on what is best that they ignore that “best” might be a range or might depend on your goals. If your goals are show chickens, higher protein levels are better. Show chickens are bred to have bigger bodies and need more protein to grow bigger and maintain that extra body mass. When the feathers are growing it will help the feathers come in nicely, plus if you drizzle some vegetable or mineral oil on their feed the feathers will be even more shiny and attractive. Diet is important to show chickens. I don’t have show chickens.
People constantly misunderstand the terms “can” versus “will”. I haven’t read all those studies MeepBeep posted but I have some. They do not say that every single chicken in the flock will develop those problems if they are fed too much calcium. Some won’t. What they say is that the incidence of internal organ damage or skeletal damage across the flock will increase under the conditions of that study.
I might as well do this here then get back to your question. I think it is relevant to you, it applies to protein as well as calcium. Of course those studies are in lab conditions. They are paid for by the commercial chicken industry. They don’t free range their chickens. Their chickens don’t get fed any treats either. Their diet is strictly regulated. The goal of the commercial industry for those studies is to determine what diet produces the best gains for the minimum costs under their highly controlled conditions. Their conditions include not only what they eat but light and other things are strictly controlled. They use special hybrid chickens for meat production or egg production. They don’t use our dual purpose chickens or our decorative chickens. They don’t keep them the way we keep them. If you have thousands of chickens in one chicken house and you have several chicken houses, just a small change in mortality, deformity, or loss of efficiency has bigger repercussions that if you have a small backyard flock. These commercial studies show that while excess calcium “can” possibly cause a problem with an individual hen, it “will” cause increase mortality, deformity, or loss of efficiency across the entire huge flock.
Another important thing that is often ignored is that one bite won’t kill them. It’s not about how much protein or calcium is in one bite, it’s about how many grams of protein or calcium they eat during the entire day. One day doesn’t matter that much either, it’s over a period of many days. It is a cumulative effect, not an immediate effect. The more your chickens forage for their own food or the more treats you feed them the less impact what you feed them has. If someone provides everything they eat, then these warnings apply to them more than if the chickens forage a lot. If you have a broody hen raising chicks with forage available, she will take them to the feeders for some food but the majority of what they eat comes from forage. At least that is the way mine do it. A few bites of Layer isn’t going to have nearly the effect on them that it will if Layer is all they eat. This is the main reason people whose chickens forage a lot don’t have the same problems as people who provide every bite of their feed.
Higher levels of protein “can” cause your hens to lay larger eggs than they otherwise would. Commercial laying chickens have relatively smaller bodies and lay lots of large eggs. They have determined that if they feed their hybrid laying flock a feed with about 16% protein and around 4% calcium their chickens are able to maintain their bodies and stay healthy and produce a lot of Grade A large eggs. For their commercial hybrids that’s the most efficient model. Most of us don’t have the commercial hybrids.
There are another factors in that efficiency. Since higher protein “can” cause the eggs to be larger, hens that consistently lay large eggs for their body size are more prone to prolapse, become egg bound, or internal lay. Lots of hens lay a lot of huge double yolk eggs and don’t have these problems. It’s not that these large eggs “will” cause these problems each and every time, but across the huge flocks they have the increase in medical problems “will” be seen. Some people on this forum do have the commercial hybrids, our hatcheries offer them. Of course I don’t have detailed knowledge of how forum members manage all their chickens but I’ve noticed that some people that complain about how the commercial hybrids are so prone to prolapse, internal laying, and or becoming egg bound often feed a higher protein diet. They want to do what’s best for their girls so they feed them well. Excess protein is not the only reason these chickens have these problems. The commercial hybrids are as specialized in producing eggs as the commercial broilers are in producing meat. Their systems are more delicate than our dual purpose hens. They are more prone to these problems in any case. Breeding does matter. This is just me talking, I don’t think high levels of protein helps.
There is another reason the commercial industry doesn’t feed a higher protein level. A hen is programmed to release one yolk at a time. If two yolks are released at the same time you might get a double yolked egg. You might get two different eggs. If that second yolk is released later you will get two eggs in one day. Commercial operations don’t like this. The double yolkers not only increase the medical risk (however small that increase really is to the individual hen) but those big eggs don’t fit their cartons. They are rejects that are sold to people that crack eggs when they use them, like bakeries or for pet food. They get less money for those eggs plus they cause special handling. Not efficient at all. A hen’s body makes a certain amount of egg material in a day, especially the shell gland. It’s pretty common that the second egg is thin or soft shelled. These can easily break and make a mess in the nest or handling equipment. At best these thin shelled eggs are rejects and sold at a lower price but often they are just a mess. There is another problem with two eggs at the same time. If two eggs are in the shell gland together, even if they both get a coating of enough shell material, there will be scars and deformities. More reject eggs. One big cause of hens releasing excess yolks is a high protein diet.
In my short answer I said all this is pretty irrelevant to you. I doubt that you have the commercial hybrids. You probably have chickens with bigger bodies that can use the extra protein to maintain those bigger bodies. They are not as efficient as the commercial hybrids at converting protein to larger eggs. They have bigger bodies so they can better handle larger eggs anyway. But the biggest factor is that yours forage so much. What you actually feed them is probably such a small part of their overall diet that it doesn’t have a huge effect. I don’t think it matters if you feed 16%, 22%, or somewhere in between. I think yours will be healthy, active, and lay a lot of nice eggs whatever you feed them. And as MeepBeep said, their bodies will shed most of the excess protein out their rear end anyway.
