Baba Basra 2:5-6

Baba Basra 2:5

A ladder must be placed at least four cubits (about six feet) from a pigeon coop to keep weasels from using it to jump to the birds. A wall must be four cubits from a rain gutter so that the homeowner will have room to place a ladder for access. A pigeon coop must be 50 cubits (about 75 feet) from a city (so the birds won’t eat the residents’ seed) and one may not build a pigeon coop on his own field unless he owns land for 50 cubits in each direction. R. Yehuda says one must have enough land to plant four kor (75,000 square cubits), which is how far a pigeon will fly. If he bought a pigeon coop, even if the land it occupies is only enough to plant a quarter of a kav (104 square cubits), it is accepted based on precedent.

Baba Basra 2:6

A young pigeon that is found within fifty cubits (about 75’) of a coop belongs to the owner of the coop; beyond that, it belongs to whoever finds it. If it is found in between two coops, then it belongs to the one whose coop is closer. If it is equidistant between them, the two parties divide it between themselves.