It can be very frustrating to find broken eggshell in a nest box and to find that the hens have started an egg eating habit. Caged hens never get to see their own eggs as they roll away once laid so sitting on them is a novelty and sometimes the weight of the hen can break a fragile shell.
Usually egg eating starts with a hen laying a thin-shelled egg which then breaks or cracks when it is laid. Being curious, hens will investigate what is inside and at that point often learn that what lies within an egg is tasty once they break the shell.
Ensuring the hens have adequate calcium and protein in their diet will help to maintain good shell quality. A simple way to provide additional calcium is to save egg shells, bake them hard in the oven, then crush them finely before mixing back into the feed. Alternatively a liquid calcium supplement can be given – Zolcal D is very good and can be bought from the BHWT online shop.
Next make sure nest boxes have soft deep bedding which is clean and fluffed up daily, and if egg eating starts, purchase and place three rubber eggs in each nest box; this will fool the hens into believing eggs can no longer be broken and they will soon tire of bouncing their beaks off a rubber egg.
In order to help break the habit, check nest boxes every 30 minutes at the time when they usually lay – this may seem tedious, but if the hens cannot break eggs, they will soon find something more interesting to do.
There is an old wives’ tale that feeding mustard-filled eggs will stop hens breaking shells, but this will not work as most hens don’t seem to mind the taste. Finally, make sure that it really is the hens who are the culprits; squirrels and even crows have been known to go into coops to steal or break eggs.