2,746. Declaring Property Hefker (Ownerless)
Hilchos Nedarim 2:14
Declaring property ownerless isn’t a vow, but it’s like a vow in that one cannot retract it. Declaring property ownerless means that one announces that the property is free for anyone to take; this applies to both movable goods and to real estate. Once declared ownerless, whoever comes first becomes the owner. This includes the one who declared the property ownerless; he can come first and re-acquire the property.
Hilchos Nedarim 2:15
If someone declares his property ownerless for the poor but not for the rich, it is not rendered ownerless; property must be declared ownerless for everyone, just like Sabbatical-year produce. If someone declares his servants ownerless, those who are adults acquire themselves. When it comes to those who are still minors, whoever takes hold of them first acquires them, the same as with movable goods.