My EE has not laid a normal egg since she molted in the fall. She "lays" these every couple days and gets the nestbox all messy. She's 5 years old. Is her egg machinery worn out, or do I need to give her some kind of supplement(s)?
She has constant access to oyster shell, and I also mix ground-up eggshells into her food. She laid beautiful eggs up until last fall...I guess her fall molt and her age got to her at the same time. Funny thing is, my same-age SLW and bantam are laying better now than they ever have before!
I would nix the eggshells and only give her oyster shell. While eggshells are a good source of calcium (at least in theory) the particles of crushed eggshells are so minute that they don't remain in a hen's digestive track long enough to be adsorbed. It's like trying to add water from a fire hose to a glass with 2 Alka-Seltzers. Adding things like vinegar to the food and water makes feeding eggshells even more problematic. This is the only thing I can think of that might help you help your hen.
Five years old is "kind of sort of" old in chicken years. In my mind a one year old chicken is 24 in human years. For each additional year add 12 years. That makes a two year old hen 36 in human terms. That makes a 5 year old hen 72. Before anyone fires up their keyboard with some other formula remember there is no real relationship between a chicken and a human, physiologically.
Any chicken that should lay colored egg but only lays white no-shelled eggs has what I can only call a grave social disease. If you can do anything to help her it is limited to special food like canned dog food and canned oily fish etc. However there are a ton of incurable chicken diseases that cause laying problems. I know of nothing that can be done to rectify these health problems. To learn more checkout the web sights at the various UADA affiliated Universities.
There is nothing wrong with feeding eggshells unless it results in the hens not eating enough other forms of limestone. All hens have a reserve of calcium that they use to make eggshells.
This calcium reserve is their own bones, think of it like a hens' bones are her calcium ATM. The calcium we feed our hens is supposed to replace what the hens have already withdrawn to make earlier eggshells. If you held a gun to my head and demanded to know the reason for this hens problems I would have to say that she has a health problem with her reproductive organs. Good laying mash or pellets should already have about 4% calcium (or some other type of limestone in it) If you can segregate her and feed her from a poultry cup a table spoon or so of oyster shell in the bottom of the cup MAY up her calcium intake, but if not at least you can monitor it. Good Luck.