Which Oyster Shells On The Side?

[Kusanar]

No that's not true. Oh well......
It's needed. It works.

Lol, ok. In the end, calcium in, calcium out, put in at least as much as comes out.

 

[chickens really]

Lol, ok. In the end, calcium in, calcium out, put in at least as much as comes out.

Definitely calcium is needed to keep them from depleting the bones. It doesn't matter what time of day day they eat it......

 

[JaeG]

This article explains the science:
https://the-chicken-chick.com/making-eggs-while-she-sleeps-importance/

 

[JaeG]

No that's not true. Oh well......
It's needed. It works.

@Kusanar is correct. Overnight is generally when the shell part of an egg is being formed calling for a greater need for calcium in those nighttime hours. The bigger the pieces the longer they take to break down resulting in more time for the hen to absorb that much needed mineral while she isn't accessing food, rather than depleting her calcium stores (ie her bones) and causing them to become brittle.

 

[ChickenCanoe]

What that makes no sense. What if they consume oyster shell in the early morning? Not absorbed?...

It makes perfect sense to me. Regardless of when they eat the oyster shell, it is absorbed. But it is well documented that they normally pick up OS in the afternoon when the egg enters the shell gland. The 25+ hour egg laying cycle means that at least 70% of the eggs are laid in the morning so most days, the shell is being formed at night. Chickens transport calcium from the intestine to the uterus faster than any other animal.
If you want more documentation.

"Calcium particle size also plays a role in absorption. 'Fine calcium particles are absorbed quick, whereas coarse particles take longer to actually absorb,' Price said. Different feeding programs may see value in both options. Egg formation generally takes place in the dark periods, Price explained, so calcium may be needed at the before bed feeding. 'producers need to make sure they are supplementing calcium in the feed so that the bird doesn’t have to go to the bone to produce its egg,' she said."
https://www.wattagnet.com/articles/32592-how-hen-nutrition-impacts-egg-shell-quality

"Calcium: Provide extra calcium to the older hens @1g/bird in the form of oyster shell over and above normal requirement in summer months. Maintain the desired particle size of calcium source at the time of shell formation. The minimum size of calcium source to improve gizzard retention is about 1 mm. Solubility and absorption of calcium source must be major criteria. Magnesium content of calcium source must be as low as possible. Organic calcium is also a good option."
http://www.thepoultrysite.com/articles/1004/how-to-improve-shell-quality/

My understanding is that the oyster shell gets stuck in the crop like the grit does, it just breaks down faster, so it is being broken down and absorbed all the time, but, I think it is better if they are breaking it down at night, otherwise, the hen will have to make the shell out of her bones, then replace the bones during the day, then make another shell. If that makes sense at all

OS and especially grit get stuck in the gizzard, not the crop. But you are correct on all the other points.