This is a supplement to assist in getting good shell quality on your eggs.
If your chickens are producing poor quality or even no shells at all then they will need a supplement of calcium. Ideally via their water supply. Using Shell-aid coupled with a good diet consisting of properly formulated layers pellets will help to correct the problem.
Half of your chickens calcium reserves are found in the Medullary bones which are mobilised at each egg journey to make the shell. If those reserves are low and the diet doesn’t contain enough calcium then thin shells can be the result. Laying thin shelled eggs or shells with no-shell can be dangerous and also very difficult for the hen to lay. Shell-aid needs to be added to the water for a 7 day period. Ideally in the second half of the day when the calcium is most beneficial.
Whilst shell problems persist avoid feeding apple cider vinegar or spinach, as this can be counter productive. These foodstuffs can stop the absorption and utilisation of calcium.