You’ll probably get different opinions on this but yes, my opinion is that you can feed too much of anything, including protein. Sometimes my opinions are not real popular.
If you look at the different feeds they normally list what birds they are intended for. You won’t find chickens listed on higher protein feeds. There is probably a reason. I’m only talking about chicks intended to be part of a laying flock. Chickens meant to be eaten or show chickens are different.
When they first hatch chicks do best on a high protein diet. The protein range I normally see for Chick Starter is 20%, but I have no problems personally feeding them as high as 24% the first few weeks. I do that when raising turkeys with the chicks. The higher protein helps them feather out faster and get off to a good start. But after they are feathered out and have that great start, they don’t need that much protein. Commercial operations that want to maximize egg production feed a lower protein feed, usually around 16%, to slow growth and match their growth rate to skeleton growth rate and internal organ maturity after 4 weeks or so on a higher protein feed. They don’t want their chickens growing too fast or laying too soon. They even cut back to a 15% protein feed after about 13 weeks to slow them down some more. If they eat a higher protein feed they normally start laying earlier. Commercial operations don’t want those tiny pullet eggs. They want them to mature a bit so they lay bigger eggs to start with.
The more protein they eat when growing, the bigger they grow, within limits of course. Since they grow bigger they need to eat a higher protein feed to maintain that bigger body. The higher the protein in the feed the more it generally cost.
If they eat a high protein diet when laying the eggs get bigger. Some people think that’s great but think of a woman giving birth to a 10 pound baby as opposed to a 7 pound baby. Is bigger always better? Might they have more medical problems like prolapse, egg bound, or internal laying if the eggs are really huge?
A high protein diet can also cause a hen to release more than one egg yolk a day. If they are released together you might get a huge double yolked egg. If they are released with a little time difference the hen may lay two eggs in the same day. Since a hen makes a limited amount of material for her eggs the second egg can be weird, like have a really thin or soft shell. If the two eggs share time in the shell gland you can get a deformed shell. Some people like these weird eggs, I don’t. An occasional weird egg is not a problem, the hen’s internal egg making factory is fairly complicated and an occasional glitch is not a problem, but I don’t want them on a regular basis.
Someone on here (I think I know who but am not sure so I won’t mention names) shared a study that showed high protein level scan reduce a rooster’s fertility. (Correction: Excess calcium can cause rooster sterility, not excess protein) Avian gout can be caused by high protein levels but from what I’ve read that’s normally above 30% protein.
You’ll notice I used a lot of weasel words in here. I’m not saying any of this will definitely without a shadow of a doubt each and every time happen. I’m saying these things “can” happen if you feed too high a protein feed, not that they always do. I just don’t see the benefit in spending extra money for higher protein feeds that can lead to problems. Other than in the first few weeks I personally limit the maximum amount of protein I feed them to 20% and generally use 16%.
There is another side to this. It’s not about what is in one bite. What counts is the total grams of protein they eat in a day, and that is spread out over several days. If they eat a lot of lower protein stuff in addition to the higher protein feed, it balances out better.
