From: Rabbi Moshe Sofer
To: Rabbi Moshe Tzvi
After a treifah gizzard was found among five geese whose ownership had been divided through sequential sales, the Chasam Sofer rules that lifting a goose to acquire it — even within the same house — constitutes valid halachic separation (pirush), and that kol d'parish requires only a simple majority rather than a 2:1 ratio. Due to the significant financial loss involved and the possibility that kavua is only a rabbinic prohibition, one who is lenient has halachic support.
Source: Shu"t Chasam Sofer YD §99