Mishna: An egg which is laid on Yom Tov: Beis Shammai: It may be eaten. Beis Hillel: It may not be eaten.
Rav Nachman: The egg is muktzeh.
Rabbah: The egg is forbidden because of Hachana.
Rav Yosef: The egg is forbidden because of gezeiras peiros hanoshrin.
Rav Yitzchok: The egg is forbidden because of gezeiras mashkin shezavu.
Challenge: Beraisa: An egg that was laid on Shabbos or Yom Tov may not be handled [it is muktzeh], and it cannot be used to cover a jar or to support a wobbly bed [this can be accomplished if you know how to handle an egg properly]. A utensil may be moved in order to cover it up [although it is completely muktzeh, like a stone or money, it is still permitted to handle something permitted in order to protect it (not everyone agrees with this, but it is the opinion of this Tanna and this is how we pasken)]. A safek is forbidden and even if it is mixed in with a thousand others, it does not become battel.
This [that a safek is forbidden] would be right according to Rabbah, because it is a safek in Hachana, a Torah prohibition, but according to Rav Yosef and Rav Yitzchok, it is a safek in a D’Rabbanan position and we should be lenient?
[This question is not asked about Rav Nachman’s opinion because muktzeh is stricter than a standard D’Rabbanan, Tosfos. Some say we don’t even consider Rav Nachman’s terutz because it was abandoned].
Resolution: The second part of the Beraisa (about a safek and a mixture) is discussing a new “egg-topic” - eggs of a tereifah, which is D’orayso.Challenge: If so, why does a mixture not become battel? If it is discussing an egg laid on Yom Tov, it is a davar sheyesh lo matirin [something which will anyway become permissible - after Yom Tov - and is thus not battel], but why shouldn’t a tereifah become battel?
You might suggest that an egg is considered too important to become battel [a chaticha hare’uyah l’hischabed, for instance, something one would serve to a guest, is considered important and is not battel].
This is dependent on your reading of a Mishna: If you read it “anything that is counted”, eggs are sometimes sold by count. But if you read it “things that are counted”, eggs are not always sold by count and wouldn’t be considered important enough to not be battel.