We are continuing in siman 3, discussing the concept of b’nei tarbus, an animal which is domesticated.
It is clear that if an animal rebels and has become a wild animal it is no longer considered domesticated. There is a question regarding something which was in a state of capture and then lost its full extent of capture (e.g., it was in a small enclosure and then the door opened). The Elya Rabba holds that if it was an animal which would not return from outside on its own volition, if it was put into a house before Shabbos, and then the door was opened on Shabbos and remained open for some time, it would be assur to close the door.The Chayei Adam points out that his opinion differs from the Magen Avraham, who holds that if the animal was already captured once and put into the house, even if the door is opened, closing the door is not a new action of tzad. Neither the Chayei Adam nor the Mishnah Berurah follow the Magen Avraham.
The Chayei Adam continues, and writes that the same halacha would apply to the shed or pen door opening up.
In siman 4, the Chayei Adam writes that geese, chicken or cats that are already accustomed to being in a home and always return home at night are considered domesticated, so enclosing them is not tzad. However, if one is concerned that it will be stolen or the like, if the animal avoids the human when the human tries to catch it, there would be an issur of tzeida derabanan to enclose it. If it accepts the human’s touch, there is no issue of tzad.
However, we have to discuss whether muktza would be an issue. Live animals are muktzah, so carrying the animal should be a problem of moving muktzah. Therefore, the Chayei Adam clarifies that one can push the animal from behind but cannot directly carry it. In regards to chicken, even holding them is assur, because they tend to raise themselves, and one ends up carrying them. Larger animals, which do not lift themselves up, can be held by their neck or by their sides, assuming there is an eruv. Either way, one cannot lift or carry it.
If the animal is not easily trappable, it is assur to trap it, even if it generally returns home at night.
Summary
The fourth condition necessary for tzad deoraysa is that the animal is not already domesticated. An animal which is semi-domesticated is assur miderabanan.
It is assur to close the door on an animal which was in an enclosure with the door open for some time.
It is muttar to enclose an animal which is fully domesticated, as the melacha of tzad does not apply to them. “Fully domesticated” is defined as accepting human touch. If it does not accept human touch, it will be considered tzad miderabanan to enclose it.
