Is the machlokes between Rav and Shmuel/R'Yochanan perhaps reflecting the machlokes between R' Shimon and R' Yehudah regarding muktzeh - where Rav holds like R' Yehudah regarding muktzeh and Shmuel/R'Yochanan hold like R' Shimon and allow the Efor'ach since it might hatch on Yom Tov and become permitted once schected?
Avraham Sacks, Ramat Beit Shemesh
1) The Gemara Shabbos 128a states that Rav holds like R' Yehudah concerning what is Muktzeh to eat, and like R' Shimon concerning what is Muktzeh to move around. According to this, Rav would not allow eating the chick born on Yomtov but he would allow moving it. Gemara Shabbos end 44b also states that Rav holds like R' Yehudah. Pnei Yehoshua here DH Ella writes that it is obvious to Rav, all over the Talmud, that Muktzeh and Nolad is forbidden.
2) Tosfos here DH Ho'il cites the Gemara Shabbos 156b that Rav said that the Halacha follows R' Yehudah, and Shmuel and R' Yochanan said that the Halacha follows R' Shimon. Tosfos writes that Shmuel and R' Yochanan did not need to say the reasoning of Ho'il u'Matir Atzmo b'Shechitah according to their opinion that anyway we pasken like R' Shimon. This reasoning is only necessary in order to show that the new-born chick is permiited even according to R' Yehudah.
KOL TUV
Dovid Bloom
Thank you very much.
The Rabbi wrote below "This reasoning is necessary only in order to show that the newly hatched chick is permiited even according to Rebbi Yehudah" - how could it be permitted according to Rabbi Yehudah?
The Gemara states that according to Shmuel; and some say Rabbi Yochanan; the chick that was born on Yomtov is not Muktzeh. Rashi DH Ho'il explains that the birth achieved 2 purposes. It permitted the chick to be slaughtered, which was forbidden before it was born. Since it achieved this, it also achieved the second purpose of removing the prohibition of Muktzeh that existed before it was born. Rashi writes that since the birth prepared the chick to be slaughtered it also prepared it not to be Muktzeh. Tosfos DH Ho'il writes that this reasoning applies even according to R. Yehuda. Whilst generally speaking R. Yehuda is stringent with respect to Muktzeh, here he agrees that the prohibition of Muktzeh disappears since the birth prepared the chick to be allowed through Shechitah.
Chodesh Tov
Dovid Bloom