Related for Beitzah 73:20

If “it and its young” fall into a cistern, R. Eliezer says: The first is brought up to be slaughtered and slaughtered, for the second he prepares a feeding place on the spot lest it perish. R. Yehoshua says: He brings up the first to slaughter, but do not slaughter it, but uses cunning and brings up the second to slaughter. If he does not want to slaughter any of them, he is free to do so.