To chase off cabbage moths.
You need a chook (hen) with no coloured feathers at all that is totally white, when she lays an egg use the egg as you wish, and keep the shell and break this up and place around tomatoes or other cabbage moth food plants.
I don't know weather it is the shell or the smell of the egg or both but cabbage moths will fly away leaving your plants alone. Dont believe me try it but it must be a totally white egg from a totally white hen.
Why do white hens lay white eggs and brown hens lay brown eggs and black hens don't lay black eggs?