What is going on with pigeons eating sand

The pigeons eat sand to wear food to help digestion.It is best to prepare health sand artificially. Health sand can promote the digestion of pigeons and help it supplement trace elements.The owner can mix health sand into the feed and feed the pigeons.Every time you have to be fed to avoid pollution.The recipe of health sand must also be adjusted according to the different growth stage of the pigeons.If the pigeons have diluted, green stools, etc., stop feeding health sand, and then feed after the symptoms disappear.