Calcium overload

Dangers of giving chickens too much calcium

source: Darold Stenson
Country Smallholding December 2003 p13

Calcium is important for bones, teeth, and growth, and helps with muscle contraction and blood clotting. Laying hens need calcium supplements, but too much calcium can cause problems, and even kill chickens, through kidney failure. The process is slow, and birds may not become ill for some years. Affected birds may lay fewer eggs, then become less active, and may also limp

Too much calcium in the feed is one cause. Breeder feeds have higher calcium levels than maintenance feeds, and should only be fed during the breeding and laying season, not all year round.. Causes also include feeding crushed oyster shell all year, instead of stone grit, to help with digestion. Chickens should have access to grit all the time, and only be given oyster shell a month or so prior to starting to lay, with the oyster shell withdrawn at the end of the laying season. Breeder feeds, with their higher calcium levels, are designed to boost egg production, and reducing calcium levels may affect production, so chicken keepers may also need to think about whether their birds should have more natural lives, with lower calcium levels, and laying fewer eggs.