I understand that you've supplemented her calcium, but did you also offer D3 supplementation? D3 is supposed to help with their utilization of the calcium offered.
Edited to add:
Vitamin D3 is required for the normal absorption and metabolism of calcium and phosphorus. A deficiency can result in rickets in young growing chickens or in osteoporosis and/or poor eggshell quality in laying hens, even though the diet may be well supplied with calcium and phosphorus. Abnormal skeletal development is discussed under calcium and phosphorus imbalances (see
Calcium and Phosphorus Imbalances) and manganese deficiency (see
Manganese Deficiency).
Laying hens fed a vitamin D3–deficient diet show loss of egg production within 2–3 wk, and depending on the degree of deficiency, shell quality deteriorates almost instantly. Using a corn-soybean meal diet with no supplemental vitamin D3, shell weight decreases dramatically by ~150 mg/day throughout the first 7 days of deficiency. The less obvious decline in shell quality with suboptimal, rather than deficient, supplements is more difficult to diagnose, especially because it is very difficult to assay vitamin D3 in complete feeds.
There is a significant increase in plasma 1,25(OH)2D3 of birds producing good versus poor eggshells. Feeding purified 1,25(OH)2D3 improves the shell quality of these inferior layers, suggesting a potential inherent problem with metabolism of cholecalciferol.
Retarded growth and severe leg weakness are the first signs noted when chicks are deficient in vitamin D3. Beaks and claws become soft and pliable. Chicks may have trouble walking and will take a few steps before squatting on their hocks. While resting, they often sway from side to side, suggesting loss of equilibrium. Feathering is usually poor, and an abnormal banding of feathers may be seen in colored breeds. With chronic vitamin D3 deficiency, marked skeletal disorders are noted. The spinal column may bend downward and the sternum may deviate to one side. These structural changes reduce the size of the thorax, with subsequent crowding of the internal organs, especially the air sacs. A characteristic finding in chicks is a beading of the ribs at the junction of the spinal column along with a downward and posterior bending. Poor calcification can also be seen at the epiphysis of the tibia and femur. By immersing the split bone in a silver nitrate solution and allowing it to stand under incandescent light for a few minutes, the calcified areas are easily distinguished from the areas of cartilage. Adding synthetic 1,25(OH)2D3 to the diet of susceptible chicks reduces the incidence of this condition. Although response is variable, results suggest that some leg abnormalities may be a consequence of inefficient metabolism of cholecalciferol.
In laying hens, signs of gross pathology are usually confined to the bones and parathyroid glands. Bones are soft and easily broken, and the ribs may become beaded. The ribs may also show spontaneous fractures in the sternovertebral region. Histologic examination shows decreased calcification in the long bones, with excess of osteoid tissue and parathyroid enlargement.
Dry, stabilized forms of vitamin D3 are recommended to treat deficiencies. In cases of severe mycotoxicosis, a water-miscible form of vitamin D3 is administered in the drinking water to provide the amount normally supplied in the diet. In cases of impaired liver function, metabolites of vitamin D are the usual choice for treatment.
https://www.msdvetmanual.com/poultr...ement-poultry/vitamin-deficiencies-in-poultry
