Eggs with pimpled eggshells are a problem for egg producers and for exhibition flocks.
Pimpled eggshells often do not hatch.
Goodson-Williams, Roland, and McGuire studied the effects of vitamin D3 in a corn-soy diet. Commercial poultry feeds use corn and soy beans to provide protein. This study gave 78 week old Single Comb White Leghorns feed with 0, 138, 275, 550, 2200, 22,000, 44,000, and 88,000 ICU of D3 per kilogram of feed.
Feed consumption, egg production, egg weight, egg specific gravity, and pimple score were determined weekly or biweekly over a 10-week period. The last step of the experiment sacrificed the hens to measure the calcium, sodium, potassium, and ash content of the uterus and serum calcium levels.
There was a linear increase in pimple score, uterine ash, and serum calcium as dietary levels of D3 increased. Egg production and egg specific gravity varied quadraticly on D3 level, uterine sodium levels declined as D3 increased, but potassium values showed no effect. The level of calcium in uterine tissue increased with increased D3. Hens fed the lowest (0 ICU/kg) and the highest levels of D3 (88,000 ICU/kg) ate much less food.
The authors concluded that eggshell pimpling is directly related to level of cholecalciferol (D3) in the diet.