How many days before the egg of pigeon become pigeon?

Your question contains a factual inaccuracy. Pigeons, like all other birds, hatch from eggs. The time for an egg to hatch varies and depends on the bird species. In the case of pigeons, it generally takes around 18 to 20 days for the eggs to hatch after they have been laid. During this period, the parents take turns incubating the eggs to maintain a suitable temperature for the developing embryos. Once the eggs hatch, the newly emerged pigeons go through various growth stages as they are cared for and fed by their parents until eventually they are able to fly and fledge on their own.