This frequent phenomenon may be caused by several factors:
- Thin eggshell – the eggshell becomes thin due to a lack of minerals especially in the case of intensive egg laying. Hens may accidentally break an egg; the contents spill out and the hens learn to consume eggs and this may even develop into a bac habit. Hens may then destroy the laid eggs by deliberate pecking into the eggshell.
- This may also be caused by other nutritional shortcomings – a lack of protein or vitamins.
- Insufficient space with lacking stimuli for natural activities (scratching, dust bathing, collecting fodder).
- Unsuitable laying nests with increased likelihood of damaging eggs.
The first two causes can be prevented simply by feeding a complete fodder mixture for laying hens with sufficient calcium contents (hens need 3 – 5 grams of calcium per day), or by providing vitamin and mineral supplements (if you only feed the hens grain or household leftovers). When a bad habit develops, eliminating this is problematic. Measures need to be taken to remove all eggs immediately after they are laid, for example using especially constructed laying nests. Sometimes excluding the laying hen that eats eggs from breeding is the simplest solution because the hen cannot unlearn this habit.