1. Machlokes regarding one who sheared and sold his sheep one by one

גזז ומכר ראשונה – if one owned five sheep and sheared and sold them one by one (keeping the fleece), so that when he finished the fifth shearing, he no longer owned five sheep, Rav Chisda says he is obligated to give ראשית הגז, דהא גזז – because he sheared the fleece of five sheep, each of which was his when he sheared it. Rebbe Nassan bar Hoshaya says he is exempt, because בעידנא דקא מלא שיעורא – at the time when the minimum shiur of five shorn sheep is completed, בעינן צאנך – we require the sheep to be “your flock,” whereas here it is not. The Mishnah on Daf 135a taught that if one purchases the fleece of five sheep from an idolator and shears them, he is exempt from ראשית הגז, since they were not his. This implies that if he purchased צאנו לגזוז – [the idolator’s] flock to shear (i.e., to own the sheep until shearing them), he would be חייב, even though each individual sheep returns to the idolator after being shorn!? The Gemara answers that the Mishnah’s implied ruling can be where the Jew acquired the sheep for thirty days (for example), and continues to own them after their shearing.

1. ראשית הגז when the fleece was sold to another Jew

The Mishnah taught that if one buys unshorn fleece from another Jew, then אם שייר – if [the seller] retained some fleece, he must give ראשית הגז for all the fleece, but if he sold all of it, the buyer must give ראשית הגז. Rava ultimately explains that this follows the Tanna who taught, regarding זרוע לחיים וקבה, that if one sold a cow’s בני מעיים, which include the קיבה, the buyer gives it to a Kohen, and its value is not deducted from the purchase price. This is because מתנות דכהן לא מזבין איניש – a person presumably does not sell a Kohen’s gifts. Since the seller retained them, his obligation to give them to a Kohen remains in force. Here, too, in a sale of fleece, we assume the seller does not sell the Kohen’s מתנות. Therefore, if the seller retained some of the fleece for himself, he must give the ראשית הגז of all the fleece to the Kohen, because the buyer can say: מתנה דכהן גבך היא – the Kohen’s gift is with you. If he did not retain any fleece for himself, the buyer must give the ראשית הגז to the Kohen (although he does not own the sheep), because the seller can say that he never sold the ראשית הגז to him.

1. שילוח הקן applies to chullin, not kodashim, nor to a bird which killed someone

The twelfth Perek begins: שילוח הקן נוהג בארץ ובחו"ל – the mitzvah of sending away the mother bird from the nest applies both in Eretz Yisroel and outside Eretz Yisroel, and during and after the Beis Hamikdash, but only to chullin birds, not to kodashim. In contrast to כסוי הדם, שילוח הקן only applies to birds, and only בשאינו מזומן – that which is not “prepared,” i.e., not in his possession. Birds of hekdesh are excluded from שילוח הקן because the passuk says: שלח תשלח את האם – you shall surely send away the mother bird, implying: במי שאתה מצווה לשלחו – the mitzvah is with [a bird] which you are commanded to send away to freedom, יצא זה שאי אתה מצווה לשלחו – excluding this [bird of hekdesh], which you are not commanded to send away to freedom, אלא להביאו לידי גזבר – but rather to bring it to the hands of the Mikdash treasurer. Ravina adds that, therefore, עוף טהור שהרג את הנפש – a kosher bird which killed a person is exempt from שילוח הקן, because the same derashah also excludes this bird, which you are not commanded to send away to freedom, but to bring it to Beis Din to be judged and killed.