Calcium for pastured laying hens

[Chris King]

My hens are fed a premium organic layer pellet free-choice (and they eat a lot of it!), but they are also on pasture all day, every day, year-round. They've typically started laying at around 16 weeks of age and their eggs are fantastic, but I've noticed a decline in egg shell quality in my most consistent layers after a couple of years of laying. By that, I specifically mean thin, fragile shells.

This problem is immediately responsive to supplementation with yoghurt or kefir (as in, thicker shells within 2 days), so I've come to the conclusion that their total diet is slightly deficient in calcium. The layer pellets contain the recommended amount of calcium for laying hens, but they're formulated to be pretty much a complete ration, whereas my hens are also eating a wide variety of plants, bugs, grubs, earthworms, etc. which changes with seasonal availability. The topsoils in this part of the country can be marginally or frankly calcium deficient, so I'm thinking that over time my hens aren't getting quite enough calcium when they're laying around an egg a day. (No problems with egg shell quality in the hens that lay less frequently.)

I've offered oyster shell grit in the past, but not only do the hens ignore it (other than the inquisitive initial exploration), I don't believe it's a particularly bioavailable form of calcium for laying hens in immediate need of supplemental calcium.

This problem is surely one that other producers of pastured laying hens have come across, so I'm wondering what other palatable sources of calcium I can supply that prevents the decline in shell quality without overburdening the body with excess calcium. (Buying yoghurt each week for 18 hens is becoming a bit of a financial burden…)

Thanks!

 

[lazy gardener]

Free range birds normally have access to lots of calcium in a forage that includes lots of weedy materials. Clover is particularly high in Ca++, as are dandelion greens. Clover is also high in protein. I would suggest overseeding your land with white or red clover, depending on how short you keep the grass there. But, if your soil is Ca++ deficient, then... the plants most likely will be also. You could put down some sort of soil amendment. Check with your local Ag extension office and see what they recommend. You have done a soil test, yes? Does the assessment and recommendation portion of that test tell you how to remedy?

You can save all of your egg shells and feed them back to the birds. My birds prefer egg shell, but if I leave OS out in a dish, they will eat it over time.

IMO, Ca++ is only a very small part of the egg shell quality issue. I've found that when I put my flock on multi vitamins, there is an immediate improvement in the entire structure of the egg, including yolk membrane, and albumen height.

Finally, if you have not looked at fermenting your feed, I suggest that you give it a try. Very good return in economy and health of your birds for the minimal time invested.

 

[Chris King]

As chicken egg shells are 95-97% calcium carbonate, egg shell quality (thickness and hardness) is restored within 24-48 hours of providing my hens with a highly bioavailable source of calcium (yoghurt or kefir), and their diets contain a great variety of both plant and animal material (fresh and naturally fermented) - i.e., they're getting plenty of protein, vitamins, minerals (macro and micro), essential fatty acids, enzymes, microbes, etc. - I'm confident that the problem is primarily one of dietary calcium insufficiency. I'm seeing the problem primarily with my high producers, so the calcium insufficiency evidently is marginal, becoming a frank deficiency only in the hens that are churning out an egg a day most days, and only after the hens have been laying for 2 years or more.

I just read an interesting review paper on egg shell quality which advised the use of large-particle calcium sources, such as oyster shell grit, instead of ground limestone, so perhaps I'll give the oyster shell grit another go.

Hunton, P. (2005). Research on eggshell structure and quality: an historical overview. Revista Brasileira de Ciência Avícola, 7(2), 67-71.
https://dx.doi.org/10.1590/S1516-635X2005000200001

 

[GC-Raptor]

I wrote in another thread about thin shells and soft shells. I feed a layers pellet feed and oyster shell in a separate container. I have been getting some soft and thin shells lately. They are consuming about a third of the feed this summer, compared to last winter early spring, and they don't seem to be consuming the oyster shell.
I free range 2 hours before sunset daily, weather permitting. They are scratching around the woodlands of my property, . And they are finding a lot of worms and bugs.
So unless I don't let them free range, I will have to wait till the weather cools and there are less bugs and worms and they eat more layers feed for the calories to keep warm. GC

 

[Chris King]

So unless I don't let them free range, I will have to wait till the weather cools and there are less bugs and worms and they eat more layers feed for the calories to keep warm. GC

I'd rather keep my hens on pasture and figure out a cost-effective way of supplementing their varied diets with extra calcium. I think they're healthiest when they're on pasture all day, all year 'round; and the eggs they produce are glorious. I won't pen them up during the day just so that they'll eat more layer pellets.

As for supplemental calories, in the winter months I feed them scrambled eggs, made from the older eggs I have in the fridge. (I feed the even older eggs to my garden, and I use all of the egg shells in my garden as a slow-release calcium soil amendment [tilled in] and as a slug deterrent [on the surface].)

It really is great fun having chickens as my 'livestock', but I think mine are falling through the cracks of the animal science/nutrition research, given that the scientifically formulated layer ration comprises only part of their daily diet - and it's a largely unknowable proportion because it varies from day to day. I wouldn't have it any other way, but it does rather leave me scrambling to figure out how to meet all of the nutritional needs of my little flock of 'production animals'.

 

[lazy gardener]

I'd give the egg shells to the birds instead of putting them in the garden.

 

[Chris King]

My concern is that the particles of egg shell may be too sharp and could damage the mucous membranes of the upper digestive tract. I don't have a way of pulverising the shells, and I think the particle size my blender or food processor produces is still too large to be entirely safe. Perhaps I'm wrong; I'm just not willing to take the risk, as it's really my chickens who are unwittingly assuming the risk.

 

[Chris King]

Besides, my hens get to pick through all the scraps from my garden, and for part of the year in the garden beds themselves, so by feeding the soil with eggshell calcium I'm feeding it to myself and my hens. In this way, I'm recycling all of the eggshell calcium on the farm. It's just not keeping up with the intense demands of the high-production layers for part of the year, hence the need for a more readily available source of calcium in this circumstance.

 

[lazy gardener]

Many of us feed egg shells to our chickens. I simply toss a bowl full of dry shells on the ground and stomp them with my foot. The chickens take care of the rest. Never an issue with the shells being "too sharp". Egg shell provides the "readily available source of calcium" that you are looking for.

 

[Chris King]

Thanks, but I won't be doing that.