Rabbah: The egg forbidden by the Mishna is not muktzeh, there’s a problem with Hachana.
In a case where a Yom Tov is Sunday, “an egg laid today was finished yesterday”, thus Shabbos made Hachana [preparation] for Yom Tov, which is forbidden by a possuk.
Abayye: What about an ordinary Yom Tov, which does not fall on Sunday? Our Mishna prohibits eggs laid on Yom Tov regardless of which day of the week it is.
Resolution: There is a gezeirah lest the egg be permitted even on a Sunday.
Question: What about every Shabbos? An egg laid on Shabbos should be permitted.
Resolution: There is a gezeirah lest the egg be permitted even on a Shabbos which follows Yom Tov
Challenge: Do we make such gezeiros? We learned in a Beraisa:
One who slaughters a hen on Yom Tov may eat completed eggs found in them [these are not forbidden due to the law of Hachana which only applies to an egg laid on Yom Tov, not to one which is still in the hen’s body]. [Why is no gezeirah enacted here?]
Rabbah: To find completed eggs inside a hen is out of ordinary and the Chachomim did not enact gezeiros for anything out of the ordinary.
Mishna: An egg which is laid on Yom Tov: Beis Shammai: It may be eaten. Beis Hillel: It may not be eaten.
Question: What is the case here? If it is a hen standing to be slaughtered, why would Beis Hillel forbid it?
Rav Yosef: The egg is prohibited because of gezeiras peiros hanoshrin - if you permit this egg you may come to permit fruits that fall off the tree on Yom Tov [these are prohibited lest one desire to eat more apples and he will transgress the biblical law of kotzeir in cutting them off from the tree*].
Abayye: Peiros Hanoshrin is itself a gezeirah, would we make a gezeirah for the gezeirah?
Response: It’s all one gezeirah [at the beginning, when the gezeirah was made, anything similar was included].
Rav Yitzchok: The egg is prohibited because of gezeiras mashkin shezavu - if you permit this egg you may come to permit liquid that seeped of grapes on Yom Tov [these are prohibited lest one desire more wine and he will transgress the biblical law of Dosh in squeezing out the tree].
Abayye: Mashkin Shezavu is itself a gezeirah, would we make a gezeirah for the gezeirah?
Response: It’s all one gezeirah [at the beginning, when the gezeirah was made, anything similar was included].
________________________________
* Tosfos: Why aren’t the apples forbidden because of muktzeh, as in the case of gentile who brings a gift of the season’s fruits?
We cannot say that this follows Rabbi Shimon who is lenient in muktzeh, Rashi there explains that even Rabbi Shimon would forbid this muktzeh.
We must say that here is a case where the fruit tree is in his yard and the fruits are “prepared” in his mind to feed his pet ravens.
But if this is the case, why is one not allowed to lead his animal to cut grass on Shabbos? Why don’t we consider it “prepared”?
We must explain that as a case where the animal is across the stream from the cut grass and couldn’t reach it without its owner’s assistance, it is thus muktzeh.
Question: Why is it not permitted to pick the fruits off the tree based on the law that Ochel Nefesh is permitted on Yom Tov? Answer 1: Only Melachos from Lisha on are permitted. Answer 2: Kotzer is specifically forbidden. [Yerushalmi].