Substitute for Oyster Shell

[MTchicknman]

I'd like to know if there is a good calcium substitute for Oyster Shell. For personal and allergenic reasons, my wife can't have anything with shellfish ingredients in it, so we dry and grind up our egg shells as a calcium replacement. However, I'd like to find another source for calcium for the needs of the hens. We feed food scraps, as well as wild bird seed, layer crumbles, and scratch to provide as much vitamins/minerals as possible, but I'd like to increase the possibility of adequate calcium for egg-laying.

Any help in locating a substitute would be appreciated. TIA

 

[chickengeorgeto]

Buy and feed free choice crushed limestone rocks. Limestone is nothing more than very very old, expired, & fossilized oyster shell. Crushed marble is another source of limestone rock that is even older, and even more past its' expiration date than good plain old limestone rock. So now you have a choice of what to use to supplement your hens' diet.

Besides not remaining in a hens' digestive track long enough for the hen to absorb much calcium carbonate from crushed eggshells, the trace minerals in oyster shell has not been absorbed by the hen or hens that previously used oyster shell to make eggshells. I am sure it makes us humans feel good to feed our chickens previously laid eggshells but I doubt that second hand eggshell does much to make a hen feel better.

 

[EggSighted4Life]

Hi.

I'm thinking limestone might be an alternative but you would have to research a little.

Also if it's nutrients your after, skip the scratch and wild bird seed. Most layer already only has 16% protein, and scratch is usually around 7%. 16% really is the bare minimum for light bodies layers like leghorn. Dual purpose gals like Rock, Orps, Wyandotte will do better with at least 18%. Scratch and wild bird seed neither have added vitamins, minerals, and importantly amino acids (that I know of). If the ratio is too high, your nutrients will be diminished too far. The seed can also be a little high in fat. Formulated POULTRY ration is the BEST you can do for them. It is meant to MEET their needs. Of course free range is a super bonus and we really have not much say over what they intake. And not all pasture is created equal. Some are bug rich and lush while others may be dry and meh. Maybe use your scratch and seed only as a treat they specially get when interacting with you and not more than 10% of the total daily intake for best result.

However, if you want to avoid the oyster shell... you're likely gonna have to avoid "layer" feed that has it mixed in usually at a rate of about 4%. I use flock raiser with 20% protein and 1% calcium. I offer oyster shell (OS) on the side free choice for layers. Unmedicated starter and grower will both have less calcium and more protein. But I'm not sure that that 1% calcium doesn't come from OS also.

One thing I will share, and I don't know if it will help you or not... But when the oyster shell is taken in by the hen, it is absorbed into her keel bone where it is then redistributed to the shell gland where it will be used to lay down the hardened egg shell material.

You wanna make sure you don't grind your egg shells to fine, or they pass through the gizzard to quickly. As long as they don't look like eggs anymore that is good. Like 1/8-1/4 inch size should be good. I don't even dry mine, well not in the oven anyways. I let them air dry and them crush a little before feeding out.

Good luck finding a supplement that suits your needs.

 

[EggSighted4Life]

Besides not remaining in a hens' digestive track long enough for the hen to absorb much calcium carbonate from crushed eggshells, the trace minerals in oyster shell has not been absorbed by the hen or hens that previously used oyster shell to make eggshells. I am sure it makes us humans feel good to feed our chickens previously laid eggshells but I doubt that second hand eggshell does much to make a hen feel better.

I hadn't heard this...

Any references would be great please? Sincerely!

 

[GC-Raptor]

Nutrena Naturewise layers feed has Calcium Carbonate, no Oyster Shell listed. I am using their Hearty Hen 18% Protein with flax seed, no Oyster Shells listed on ingredient label, 3.8% Calcium. GC

 

[lazy gardener]

I hadn't heard this...

Any references would be great please? Sincerely!

Agreed. Let's see a science based study.

 

[EggSighted4Life]

Agreed. Let's see a science based study.

Actually, come to think of it (I'm a MAJOR think everything though until it's settled in my mind type person )... I'm not providing calcium, in the case of recycled egg shells fed back to my ladies for the trace minerals that might be in original oyster shell. In fact that isn't even the reason I provide oyster shell. I provide that for the calcium that is coating the outside of the egg. They get their trace minerals that they need for general body maintenance and egg production (not the shell part) from their standard ration as far as I know. That IS why I provide a formulated feed.

 

[lazy gardener]

Just for grins and giggles, I did a bit of a search regarding bioavailability of calcium from egg shell:

https://www.ncbi.nlm.nih.gov/pubmed/15018022
Abstract
In this paper the most significant biological and clinical aspects of a biopreparation made of chicken eggshells are reviewed. Eggshell powder is a natural source of calcium and other elements (e.g. strontium and fluorine) which may have a positive effect on bone metabolism. Experimental and clinical studies performed to date have shown a number of positive properties of eggshell powder, such as antirachitic effects in rats and humans. A positive effect was observed on bone density in animal models of postmenopausal osteoporosis in ovariectomized female rats. In vitro eggshell powder stimulates chondrocyte differentiation and cartilage growth. Clinical studies in postmenopausal women and women with senile osteoporosis showed that eggshell powder reduces pain and osteoresorption and increases mobility and bone density or arrests its loss. The bioavailability of calcium from this source, as tested in piglets, was similar or better than that of food grade purified calcium carbonate. Clinical and experimental studies showed that eggshell powder has positive effects on bone and cartilage and that it is suitable in the prevention and treatment of osteoporosis.


Then, this study, comparing Ca++ supplementation in poultry diet: Oyster shell, limestone, and egg shell. Please read the whole study, if you are of an inquiring mind. I found table 2 to be quite informative.

http://macrojournals.com/yahoo_site_admin/assets/docs/2AS21Cu.237112321.pdf

 

[GC-Raptor]

So eggshells are best and half limestone and half eggshells are second and the best in feed conversion.
And for people scrambled eggs with the shells are something to think about. GC

 

[blackdog043]

@lazy gardener, Thanks, that was a good read.

And for people scrambled eggs with the shells are something to think about.

I would grind them to a powder first, don't want crunchy eggs.