calcium absorption is not solely dependent on calcium (thus oyster shel) but also on other things mainly the ratio of phosphorus to calcium and vit D3... if you live in an area where you have had your chickens stay inside for long periods due to the weather it could very well be a vit D3 deficiency...this is most easily treated by giving POLYVISOL (childrens liquid A-B-D vit supplement) at the rate of five drops a day for one week then taper off the next. You can (in addition to this) give a complete supplement such as AviaCharge 2000 (one of the few complete nutritional/vit supplements I know of where all is in the correct ratio to each other which can be used on a daily basis) .... you can order this supplement online from McMurry or Strombergs.
when mine used to do it i put oyster grit in with the food. usually they will not eat it for me by it's self free choice. i also make scrambled eggs and crush up the shells and just mix it together and they eat that no probs. if u can do something like this usually in 3-5 days the eggs go back to normal if it is lack of calcium.
i would try these things or as bay suggested before ordering or giveing them things that they probably do not need. if these things don't work an u try the vitamins, i do not reccomend to double dose them. one product with it made for poultry is pleanty going by manufacturers doseage for what they would need. u can buy a pkt of it at the feedstores or tractor supply for around $5. i do not reccomend POLYVISOL unless it is for a very sick and week bird that cannot eat or drink on it's own(and u need to get it down their throats, useing a liquid and dropper). it was not ment for poultry use and to my knowledge it doesn't contain proper amounts suited to the needs of a bird.
another thought is layena layer pellet, sunfresh recipe in a blue bag if u can find it. it is the only feed i know of sold that contains enough calcium that oyster shell is not needed. check and see if ur feedstore may carry it i know alot of them here do. it is now the only pellet i will buy for mine and since switched i haven't had to buy oyster and they r still laying up a storm with beautiful nice hard shell eggs. also it contains marigold extract which makes the yolks very orange in apearance and the eggs have tasted alot better on this feed than any others we used to use.
hope this helps ya,
A vitamin is a vitamin ... only the dosage is different ... mixing in oyster shell with the feed has never been advised and in all the veterinary and extension articles it is stated to give it free choice and not mix in with the feed. Not only will this throw the CA/P ratio off balance http://www.worldpoultry.net/poultry_phosphorus_deficiency
but by mixing in the feed you can easily get an overdose (especially if you do not separate the bird and the feed is given to the rest of the flock) which will cause organ damage and gout. http://edis.ifas.ufl.edu/PS029
The nutritional role of phosphorus is closely related to that of calcium. Both are constituentsof bone. The ratio of dietary calcium to phosphorus affects the absorption of both these elements;an excess of either one impedes absorption and can reduce egg production, shell quality and/orhatchability.
In addition to its function in bone, phosphorus plays a primary role in carbohydrate metabolism,is active in fat metabolism, and helps to regulate the acid-base balance of the body.
Excess vitamin D3 leads to increased calcium absorption resulting in hypercalcemia which may reduce egg production.Most animal species appear to be able to tolerate 10 times their vitamin D3 requirement for long periods of time. For short-periods of time, poultry can tolerate upto 100 times their requirement. An excess of vitamin D3 in the diet, therefore, is unlikely...."
vitamins contain different things for different reasons. childrens vitamins do not fully contain everything an adult vitamin does does it? no because some things a kid doesn't need and can be over dosed with or can't take as a child cause it would poison or cause harm to them or stunt growth. there is vitamins specially forumalated for just woman or just men, one a days, childrens, for this ailment or that all kinds of different ones and they can be bought seperately not all in one also. each of those kinds of vitamins contain different thing to make those special formulas so no a vitamin is not a vitamin same as any other. same thing with animal vitamins and also different companies may use different attitives an such as well as ingrediants.
that's like saying to take avia charge and mix it and let me kid's drink it for a suppliment cause a vitamin is a vitamin. doesn't make sence does it and it is potentially very harmful and/or poisonous? same thing with giveing 2 types of vitamins at same time it's over doseing on parts of the vitamins and minerals and sometimes that can be dangerous or poisonous. for instance that would be like me takeing a one a day prenatal pill and then on top of it takeing one a day over the counter vitamins. that prenatal would be more than enough and there is no reason to take the over the counter. things such as iron alone should never be over so much of a doz and can cause serious probs.
nothing personal and i'm not trying to be smart, think about what i'm trying to explain. u should not double any kind of vitamins or give to another species if the label doesn't say it is for it and the directions don't read it. alot of things ment for humans r not animal tested and could be very harmful or toxic to our poultry. chickens on a daily basis do not need a suppliment per say they should get enough from what is in their feed and only need it when lacking something or very ill.
i have never read that or ever heard of that so i can't say for sure as to what any articles say but in my experience i have always done that for years even since i was a kid with our poultry. i put in 1-2 hand fulls of oyster in self feeders once a week till i started useing this feed and have never had a prob with overdose and my roos as well as my whole flocks all eat the same thing as my girls with no probs. mine have never had organ damage and gout and r perfectly healthy.
I suggested a D3 supplement as this is often indicated specifically with softshelled eggs and after all we are coming out of the winter period where birds have been staying in (not much sunlight) and have been eating less due to cold weather and using their reserves to stay warm(see my original post in which I asked if this was an older bird which might have been inside alot during the winter months) There is also bird supplements in a pet store however,polyvisol is a childrens vitamin easily found if you do not have it in the house or have a pet store near to you which might have a specialized supplement containing only D3 (btw >the difference between a childrens and adult vitamins is dosage> the polyvisol has three vitamins all of which are often difficient in chickens following a winter/stress period (you do NOT want a "general" vitamin containing all kinds of things at the wrong dosage...if you want a complete vitamin/nutritional supplement you will need one formulated for poultry > I suggest the AviaCharge 2000 as it is "complete" however it does not provide any of the vitamins in therapeutic dosage)
Here is the link to a page which has ingredient and dosage info for the Polyvisol ..you can see that the five drops (as opposed to the capful whereby the dosage in the chart is calculated in this info sheet is far below the even the therapeutic maximum given for poultry and thus cannot possibly pose any toxicity danger. I know of no poultry supplement specifically providing only A-B-D3 (I have seen in petstores though for birds) http://www.drugstore.com/qxp38155_3..._drops_for_infants_and_children_0_3_years.htm