Gemara

(Mishnah): A Chazakah for slaves...

Question: Reish Lakish taught that there is no Chazakah for Goderos (things that can walk by itself, i.e. animals)!

Answer (Rava): They have no immediate Chazakah (one who holds them is not assumed to be the owner), but Chazakah applies after three years.

Some goats were eating peeled barley in Neharde'a. The owner of the barley seized the goats, and was claiming a large loss.

Shmuel's father: He can claim up to the goats' value, for he could have said that he bought them.

Question: Reish Lakish taught that there is no Chazakah for Goderos!

Answer: Goats are different. A shepherd watches them. (They could not walk off by themselves.)

Question: Goats walk unattended in the morning (to the shepherd's house), and return unattended at night!

Answer: There are many thieves in Neharde'a, so people do not leave goats unattended.

Bava Metzia 116a: Goats are not normally lent or rented, therefore the one who seized them has a Migo. He could have said that he bought them.

Rishonim

The Rif and Rosh (3:26) bring the Gemara verbatim.

Nimukei Yosef (DH Yachol): When he claims that the goats damaged him, he is believed only through a Shevu'ah while holding a (Kodesh) Chefetz (e.g. Sefer Torah or Tefilin). Even though there is a Migo to say that he bought the goats, it is not a full Migo. Now he says that they ate barley. This is not brazen (the owner does not know that it is false). To say that he bought hem would be brazen. We do not believe a claim that is not brazen to exempt from an oath, Migo he could have made a brazen claim. This is how Rabah explains why Modeh b'Miktzas swears, even though he could have denied owing anything.

Rambam (Hilchos To'en 10:1): If a Behemah or Chayah (domestic or wild animal) is not guarded, rather, it walks everywhere and grazes, it is not in the Chazakah of one who seized it, if it had a known owner. If Levi brought witnesses that the animal was known to be his, and Shimon, who seized it, claims 'you sold it or gave it to me for a gift', he is not believed. Possession is not a proof, for it walked by itself and entered his Reshus. Therefore, if he does not bring a proof, the animal returns to Levi. He swears Heses to refute Shimon's claim.

Rambam (2): If the animal was guarded or given to a shepherd to guard it, even if Levi brought witnesses that the animal was his, it is Muchzak to belong to Shimon, who has it now. If Shimon claims 'you sold it or gave it to me', he swears Heses that it is his, and he is exempt.

Rambam (3): Therefore, if Shimon seized Levi's animal that was guarded or given to a shepherd, and Levi claims 'it went by itself to you', or 'it is a deposit with you' or 'you borrowed it', and Shimon says 'true, it is not mine. However, you owe me this amount' or 'you gave it to for security for a debt of this amount', or 'it damaged me, and you must pay to me this amount', he can claim up to its value, for he could have said 'I bought it.' He swears while holding a Chefetz, and receives.

Magid Mishneh: The Ge'onim say that if one does not claim that the item itself (that he holds) is his, he swears while holding a Chefetz.

Rambam (4): Similarly, slaves who can walk are not in the Chazakah of the one who holds them now. If Levi brought witnesses that this slave was known to be his, and Shimon claims 'you sold him or gave him to me for a gift', he is not believed. The slave returns to Levi. Levi swears that he did not sell or give him. If Shimon brought witnesses that he has the slave for three consecutive years from day to day, and used him the way slaves serve masters, since Levi did not protest all these years, Shimon is believed. He swears Heses that Levi sold or gave the slave to him, and keeps him.

Magid Mishneh: The Rambam did not discuss Chazakah of three years for animals. A support is that the Mishnah mentioned Chazakah only for slaves, but not for animals. The Rashbam says that Chazakah of three years helps also for animals. It seems that the Ba'al ha'Itur holds like the Rambam. Shevu'as Heses applies even to land. Some say that one who has a Chazakah need not swear, like 'Chazakah' connotes.

Poskim

Shulchan Aruch (CM 72:21): Chazakah (possession) helps to claim a loan up to the value of what was seized only if it cannot walk by itself, and it stands under the owner's control, e.g. Metaltelim or a baby slave who cannot walk, or an animal guarded by a shepherd. Adult slaves or an animal not under a shepherd, rather, it walks by itself, a shepherd is not believed to say that he bought it to it is a security. If witnesses say that it is Levi's, it goes back to Levi. He swears that he did not sell it or give it for security. Seizure of them does not help, for the stray by themselves, and they are always in the owner's Reshus. If one has witnesses that he was Machazik in them for three years, he is believed, and he swears Heses that he bought them or received them for his debt.

Shulchan Aruch (135:1): Even though if Shimon possesses Metaltelim, he is believed to say that they are his, he is not believed about a Behemah or Chayah. Since it walks, we are concerned lest it walked by itself into his Reshus, or he took it while it was walking. Therefore, if Levi brought witnesses that it is his, he swears Heses and takes it.

Shach (1): Really, he swears after receiving it, like the Rambam says.

Shulchan Aruch (ibid): If Levi has no witnesses, Shimon swears Heses and keeps it. Where it is normal to give animals to the shepherd in the morning and to take them from him in the evening, and the animals never walk by themselves, they are like other Metaltelim. One who possesses them is believed through Shevu'as Heses to say that he bought it.

SMA (1): This is even if it was not a security, and he just seized it to collect a debt from it.

Shulchan Aruch (ibid): If he claims that it damaged him as much as its value, or that the owner owes him such an amount, he swears while holding a Chefetz.

SMA (2): The Ra'avad says that if one claims that other Metaltelim are a security, he is believed through Shevu'as Heses, as if he claimed that he bought it. Here, when he claims that it damaged, he agrees that he swears while holding a Chefetz, for this is less brazen than saying that he bought it. Saying that it is a security is no less brazen than saying that he bought it.

Rema: Some say that if he made Chazakah for three years, in every case it is a Chazakah.

SMA (4): This opinion does not require an oath, but only when Levi has no witnesses.

SMA (3): Chazakah of three years does not help for other Metaltelim, for it is normal to lend them for more than three years, or perhaps the owner forgot to whom he lent them. This does not apply here. The Rambam and Mechaber hold that Chazakah of three years does not help for Metaltelim, for we do not write documents for them. Therefore, it helps for slaves, but not for animals. Here, the Mechaber is like the Rambam. In Siman 72:21, it seems that he equates animals to slaves! There is not the primary place for the law, so he was not so precise. He merely taught that Chazakah of three years helps for living things, but not for Metaltelim. He did not rule like either opinion (about whether it helps only for slaves, or even for animals). Here is the proper place for the law, and he rules like the Rambam.

Shach (3): It is clear from the Gemara that all agree to this. We asked from Reish Lakish, who said that there is no Chazakah for Goderos. Rava answered that their Chazakah is not immediate, rather, it is after three years. This implies that Godros have Chazakah of three years. Also, 'Godros' refers to flock, not to slaves, like the Rashbam (DH ha'Godros) says. If slaves were unlike Godros, the Gemara should have said so, instead of explaining Reish Lakish unlike his words connote (that they have no Chazakah at all). The Rashbam, Nimukei Yosef, R. Yerucham and Semag explicitly say that Godros have Chazakah of three years. The Magid Mishneh said that the Rambam disagrees. There is no source to say so. He taught about Chazakah of three years for slaves, and the same applies to animals. He connotes that slaves and animals are the same. The Bach says so, and Perush ha'Mishnayos and the Bartenura connote like this, unlike the Tosfos Yom Tov said. The Mechaber agrees, like he said in Siman 72. The only source to say that Ba'al ha'Itur disagrees is that he said that Chazakah of three years does not apply to Metaltelim because we do not write documents for them (and this is not a solid proof). Even if the Ba'al ha'Itur disagrees, we rule like the Gemara I brought and all the other Poskim.

Gra (5): The Yerushalmi says that there is Chazakah for slaves, even though it holds that there is no Chazakah for Godros.