Effect of Various Sources and Sizes of Calcium Carbonate on Egg Quality and Laying House Performance of Red × Rock Sex-Linked Females

Supplemental calcium sources for Red × Rock sex-linked females were studied. Each of five treatments involved 16 replicates of 24 birds or a total of 384 birds per treatment. The supplemental calcium in the three diets involved was supplied by 1) granular limestone, 2) ⅓ granular limestone plus ⅔ oyster shells or 3) ⅓ granular limestone plus ⅔ calcite crystals. Beginning at 22 weeks of age Diet 1 was fed to three groups of birds and Diets 2 and 3 to the other two groups. At 42 weeks of age, two of the groups of birds receiving the limestone diet were changed to diets containing ⅓ limestone plus ⅔ oyster shells or ⅓ limestone plus ⅔ calcite crystals, respectively. There were no significant supplemental calcium treatment differences in egg production, feed consumption, feed efficiency or livability during the laying phase. Body weight differences at 72 weeks of age were not statistically significant. The results of the study indicated that large particles of supplemental calcium have no influence on shell quality if the birds are consuming adequate calcium. There was an indication that a change in calcium supplement during the laying period tends to help maintain egg shell quality to a greater degree than the feeding of a single source of supplemental calcium throughout the experimental period.