This darkening of their color is a sure sign of fertility. When the squabs have hatched, the old birds will carry the empty eggshells, which might otherwise smother the young birds, out of the nest. Now the parents will take regular turns at brooding their offspring day and night for a week or ten days, keeping them suffi-ciently warm and generally protecting them. Pigeons feed their young by means of regurgitation, with the latter inserting their tender little beaks between those of their elders, who then literally pump a soft, mushy substance, called pigeon milk, into the squabs' crops. As the youngsters grow, their crops receive less and less soft food and more small grains until, at approx-imately three weeks of age, they are quite ready to digest the hard and often quite large grains which their parents eat.
Most pigeons feed their young shortly after they themselves have eaten and drunk.
They will fill their crops with various available grains, then take some grit, and finally hasten to the waterpans, freely drinking a considerable quantity of water with which to soften the hard grains in their crops. Now that the meal for the youngsters is ready and complete, they will fly to the nest, there to regurgitate the watery mixture. When the squabs are very young, the hen does most of the feeding. Later on, when they are two or three weeks old, at which time she gets ready to start another nest, the cock assumes the feeding of the squabs. Some breeds of pigeons, such as Homers, Tumblers, Rollers, and others, are known as eager and dependable feeders of their young.