Oyster shells - necessary?

[Folly's place]

It's best to offer oyster shell separately, rather than adding it to their feed. The birds will eat what they need, and not be 'force fed' too much.
Mary

 

[Ridgerunner]

All chickens need some calcium for growth or body functions. That's why all chicken feed has some in it. Other than layer it is about 1%, sometimes more often less. When they are making egg shells, the pullets and hens need more. That's why Layer has about 4% in it, sometimes more sometimes less. If Layer is all they eat, that 4% is enough. If they eat much other low-calcium stuff Layer by itself may not be enough for the egg shells.

Chickens can get calcium from some of the things they eat. Some vegetation has calcium, often not much but some have more than others. They can get calcium from hard-shelled bugs or other creepy crawlies they eat. If your native rock is limestone or some other rock high in calcium they can get calcium from that. It doesn't matter where the calcium comes from, if their body can digest it they can use it.

Chickens do not digest all the calcium that is in the things they eat. Some of it goes right on through and out the rear end. As long as the egg shells are hard they are getting enough from somewhere. If the only calcium they were getting was from the egg shells they laid they would be in trouble. Some calcium is used for other body functions, some goes out the rear end. But since they are getting additional calcium from other sources egg shells can be a nice calcium supplement. Your egg shells will tell you if it is enough.

Many of us do not like to feed the extra calcium that is in Layer to our non-laying birds. Some don't worry about it. There has been plenty of research that shows excess calcium can be harmful to growing chicks. The mortality rate is higher in chicks fed the equivalent of calcium in Layer. That does not mean that all the chicks immediately fall over dead, just that a higher percent die than those fed a lower calcium diet. They cut chicks open to compare the damage done to internal organs, liver and kidneys. Damage is done on a high percentage of chicks on a high calcium diet. It's not how much calcium is in one bite but how many total grams of calcium they eat over the full day, and even then averaged over several days or weeks.

Then you have the non-laying chickens in the flock, roosters or hens not currently laying. Some people worry about them a lot more than others.

Most hens or pullets that need the extra calcium for the egg shells seem to know that instinctively. If they need extra calcium and a supplement is offered they tend to eat enough. The ones that don't need it may eat a bit but not enough to harm themselves. You can get some exceptions to this like everything else, but the vast majority seem to be able to handle that.

I offer oyster shell on the side. That allows the chickens to decide if they need more or not. If they are getting enough calcium from other sources oyster shell can last a long time. It never goes bad. If they are not getting enough calcium from other sources then the oyster shell can disappear fairly quickly. I practically always have growing chicks in my flock so I never feed Layer. It's either a chick starter or a grower, depending on how old the chicks are. Since I also always have hens or pullets laying I always offer oyster shell on the side. For me this takes all the guesswork out of it.

I've had pullets start laying as early as 16 weeks but that's pretty rare. Your 5-week-olds will probably start sometime after the first of the year. I have had some pullets go 9 months before they start laying, but that is really rare too. If I were you I'd expect eggs in January or February. You never know for sure but in Georgia I think you have a good chance. I'd offer oyster shell on the side after New Years. There is nothing wrong with crushing the egg shells after they start laying an offering the to the chickens. Either they will eat them or they won't.

Good luck!

 

[slordaz]

From my undeestanding, you start gibing oyster shell when they start laying. Our hens eat it, no problem. We just mix it into their feed.

You can give crushed egg shells, but you may not have a good supply of them for a while unless you already have other egg layers.

From what I have heard, oyster shell lasts in their body longer than eggshell so it is better for long term calcium supplementation.

Personally, I give my hens both. Oyster shell in their feed and I put finely crushed eggshells in the yard when they free range. They will take it as they need it.

We first got a 5lb bag at Tractor Supply to test it out and I want to say it was about $10 or so. It does last a long time. A month or two later it seems we have a bit more than half of the bag.

if you have mixed flock though you shouldn't be adding oyster shell in the feed, it can build up to toxic levels in a bird that doesn't need it.

 

[Aquatic_blue]

if you have mixed flock though you shouldn't be adding oyster shell in the feed, it can build up to toxic levels in a bird that doesn't need it.

A mixed flock? Does that mean a flock with different breeds or ages? They are all laying. All of our chickens are the same breed and roughly the same age. We put very little oyster shell in their feed. The bag says it can be mixed with food - 1lb oyster shell per 20lb of feed.

 

[slordaz]

A mixed flock? Does that mean a flock with different breeds or ages? They are all laying. All of our chickens are the same breed and roughly the same age. We put very little oyster shell in their feed. The bag says it can be mixed with food - 1lb oyster shell per 20lb of feed.

Mixed ages, a rooster or say chickens/ducks/ turkeys or any combination of.

 

[BigBlueHen53]

Yes, a mixed flock meaning laying hens and non-layers, which could be roosters, old "spent" hens, or birds too young to lay. My flock is mixed. I used to feed layer, but after coming here to BYC and listening to more experienced folks, I now feed an "all-flock" feed and keep oyster shell available in a separate feeder. Like others have said, they don't eat much and it lasts forever. I also keep grit available separately and it, too, lasts a long time. In both cases, they don't need much, but they do need it.

Welcome to BYC! Thanks for joining us! Please post an intro on the "New Members" thread so we can greet you, thoroughly and properly!

 

[Folly's place]

@Aquatic_blue , if you keep at least some birds longer, rather than practicing the 'all in, all out' commercial plan, you will have birds molting and not laying eggs, and young birds, and active layers, all at once. That's why feeding an all flock feed with separate oyster shell makes sense, because active laying hens need more than anyone else.
Mary

 

[Aquatic_blue]

@Aquatic_blue , if you keep at least some birds longer, rather than practicing the 'all in, all out' commercial plan, you will have birds molting and not laying eggs, and young birds, and active layers, all at once. That's why feeding an all flock feed with separate oyster shell makes sense, because active laying hens need more than anyone else.
Mary

I see. Good to know. We only have 4 egg laying hens that are close in age so perhaps it isn't as much of a concern at this point.

 

[PirateGirl]

I feed my chickens and ducks both eggshells back to them. I have a bowl on the kitchen counter next to the stove that any eggshell goes into, when the bowl gets full I crush them up and give them to the girls. I have been doing this as long as my girls have been laying. No washing, no baking, no special prep really. No egg eaters. I was told that the size of the calcium particles are important in terms of how fast/slow they are absorbed into the system and how usable they are for the chickens in the production of new eggs. There are some good studies on this. Essentially the eggshells fed back to the flock is not an adequate substitute for oyster shell and oyster shell should still be offered on the side for laying hens.

http://www.the-chicken-chick.com/for-strong-eggshells-size-matters/

There are more links at the end of the article as well.

 

[BigBlueHen53]

This article was very interesting, thank you! I still have one question, though. If oyster shell is the best source of calcium for laying hens, why feed egg shells at all?

Incidentally, I have always offered OS to my hens, never shells, and they do fine on it. In nine years we have had only one rubber egg, and one double yolk, probably from a nearly spent hen. The shells are so hard I have to give them a pretty good whack, sometimes two, to crack them. I don't think they need any additional calcium!