Can you tell me if I've got this straight? Tosfos says a live chick is given to quiet a crying toddler, so it is not muktzah, i'm assuming because now there's a purpose for it, as opposed to a dead chick.
Can you tell me if any Poskim are somech on this Tosfos to matir dogs that are clearly raised for the action of "petting" in part, that is their companionship implies physical pet-like interaction, as opposed to let's say a farm goat that someone would just adopt as a pet. I heard that possibly Rav Eliashiv Shlita Zol Er Gezunt Zein, had something to say about this Tosfos, but maybe not in writing.
Thanks so much for anything you find.
B'Vracha,
Mordechai Goldstein
Actually, there are two opinions brought in that Tosfos you mention. The first opinion - that of Rabbeinu Yosef - is that the chick is not Muktzah for the reason you give. The second opinion - that of Rabbeinu Yitzchak (see Hagahos Ashrei on Rosh) - is that the chick is Muktzah. If it wasn't, he says, every pretty stone and piece of wood would be Mutar (presumably because it could also be used as a pretty toy for a child). This implies that, in principal, the chick should be Mutar but that Chazal made no exceptions (Lo Pluge) in their Gezeirah of Muktzah.
This second opinion seems to be the conclusion of Tosafos and is codified by The Shulchan Aruch haRav (OC 308).
Keep in mind, though, that Tosafos is addressing the question of the status of every chick. In other words, can we say that a typical chick is considered to be useful on Shabbos and therefore not Muktzah? He is not addressing the question - which I believe is your question - of whether it is possible to designate (Meyached) a particular chick for a particular use.
We know that it is possible to be Meyached even a stone for a certain purpose, for example a door step, as long as it is permanently designated for that purpose (see Shulchan Aruch OC 308:22). Perhaps the same can be done for a house pet - a dog or a cat. Can we designate them for the purpose of, let's say, a lap warmer or perhaps as a thing that calms a person down by being petted? The Sefer Minchas Shabbos (ch. 8) addresses this question and concludes that one should be stringent in the matter. Perhaps he holds that these uses are not well enough defined.
I am not aware of a Psak that Rav Elyashiv issued on this question.
Shanah Tovah,
Yonasan Sigler
This is not a Psak Halachah