Related על ביצה 1:4

If someone has designated them in the nest and he finds them in front of the nest or at the entrance, they are permitted. R. Shimon ben Elazar said: The The house of Shammai and the House of Hillel agree that if he has found them in the nest and finds in front of the nest, they are forbidden. In what case are these words said? If they are pigeons from the dovecote or from the upper floor, or birds nesting in pitchers or in a well. But geese, Chickens or Herod's pigeons, need no determination because they are in the hands of a human, and an animal living in the park needs designation because it is not in the hands of a human. R. Shimon ben Elazar said: The house of Shammai agrees with the house of Hillel that the fasteners may be removed. What do they disagree about? About reattachment - the House of Shammai forbids it, but the house of Hillel permits it.