Rambam - 1 Chapter a Day

I.e., the difference between the value of the eggs and the value of the chicks once they have grown into chickens.

The agreement between the two is an iska arrangement. Half of the eggs are considered a loan, and half are considered an entrusted object. Hence, unless the owner of the eggs pays the chicken farmer a wage, the work that the chicken farmer invests resembles interest. I.e., it appears that he is tending to the half of the eggs given to him as an entrusted object, in consideration of the fact that he was given the others as a loan.
Some manuscripts and early printings of the Mishneh Torah also include the phrase “as an unemployed worker” in this clause. With regard to the definition of the term “unemployed worker,” see Chapter 6, Halachah 2.

I.e., the difference between the value of the animals when they were small and their value once they have grown.

For it is not until this time that one will receive a proper price for them.

See Chapter 4, Halachah 4.

I.e., the difference between the value of the animals before they were fattened and their value afterwards.

I.e., this extra amount is considered his wage.

Of the same type. Thus, he is performing the same work for his own animals as he performs for the sake of the animal that was entrusted to him. Therefore, he need not be paid a large amount as a wage.

Note the parallel in Chapter 6, Halachah 2.

Chapter 6, Halachah 3.

Without the owner’s having to pay the caretaker a wage.

And thus, one might say that caring for the portion that is an entrusted article appears as interest.

And this benefit takes the place of his wage.

And thus caring for it appears as interest.

From the Tur and the Shulchan Aruch (Yoreh De’ah 177:23), it would appear that 18 months is sufficient for cattle.

The Shulchan Aruch (ibid.) write that the owner may also require the caretaker to keep the animal for the entire duration. For, since the animal is older and eats more, greater effort may be necessary to provide for its upkeep (Turei Zahav 177:30).

For if the division is made before then, the caretaker will have invested a share of work that exceeds the measure of the profits that he could reap.

E. g., sheep or goats.

Who are knowledgeable with regard to such matters. See Chapter 5, Halachah 9.
This applies in an instance when he does not notify his partner. If he notifies his partner, the presence of three people is not necessary (Beit Yosef, Shulchan Aruch, Yoreh De’ah 177:23).

For it is part of his share of the profits of raising the other animals.

He does not have to be given a wage for caring for his colleague’s share of the animal, since he is already caring for his own portion of that same animal. (See Kessef Mishneh and Lechem Mishneh.)

By making the stipulation, the caretaker is concluding their partnership with regard to that animal, and then renewing it on different terms. If, however, he does not make such a stipulation, the original partnership continues. In such an instance, the offspring are considered part of the profits of that partnership and are divided accordingly. Note the parallel in Bava Batra 143b.

I.e., it should be considered an expense of the partnership and borne equally by both partners. If the caretaker carries the merchandise himself, he should be paid this wage (Turei Zahav 177:27).

Because handling an animal is more difficult than handling merchandise. Our translation is based on the commentary of the Lechem Mishneh. Rashi, Bava Metzia 68b and the Ra’avad interpret the phrase s’char behemah as referring to an additional amount paid for carrying the animal. For when an animal is young, there are times when the caretaker is required to carry it from place to place.

For these require even greater care.

As explained on several occasions, when a person enters into a business arrangement, unless it is explicitly stated otherwise, we assume that he agrees to follow the locally accepted norms.

Landed property is considered to remain in the possession of its owner at all times. Hence, there is no concept of a loan involved, and therefore no question of interest. Indeed, the Sages of the Mishnah themselves would employ sharecroppers (Kessef Mishneh).

We assume that the two agreed to divide the profits according to the ratio that prevails throughout the local community.

Witnesses to the agreement or a signed contract.

I.e., is knowledgeable about farming and would till the land himself if he could not find a sharecropper to till it [Rashi (Ketubot 80a)].

For it was the husband who hired them, and their contract is with him (Hilchot Gezelah 10:12).

See Hilchot Gezelah loc cit., which explains that they are considered having tilled a person’s property without permission. Therefore, they are judged at a disadvantage. If they increase the value of the field more than they spend, they are given only their expenses. And if the value of the field has not increased as much as they spent, they are given only the amount of the field’s increase in value. See also Hilchot Ishut 23:9.
The reason for this severe ruling is that the woman could tell the sharecroppers: “These are the conditions that my ex-husband would have had to abide by. Had you not accepted the field, he would have had to till it. Hence, I should not be forced to lose any more than I would if he had tilled it” (Kessef Mishneh).

I.e., whether or not she was married, the woman would have hired them. Hence, they are given the advantage in court if the woman desires to have them removed. If they spent more than the increase in the value of the field, they are reimbursed for their expenses. If the field’s increase in value exceeds their expenses, they are reimbursed for the increase in value.

See Hilchot Nachalot, Chapter 9, which explains these concepts in greater detail.
From that source and from the Rambam’s Commentary on the Mishnah (Bava Batra 9:4), it appears that the guiding principle is that as long as they do business as a group, they are judged as partners. If, however, one of the brothers or partners invests his own money or effort into a separate enterprise, that is considered a private undertaking.

See Hilchot Nachalot 9:6, which explains that this ruling applies when the person is appointed to this position because of his father - i.e., the king says: "Let us perform a kindness to the orphans." If, however, the king appoints the son because of his own merits - without considering those of his father - he is entitled to the profit himself.

The Shulchan Aruch (Choshen Mishpat 177:2) rules that before paying for the cure, the partners may elect to dissolve the partnership.

For his sickness is considered an act of God to be borne by all the members of the partnership.

E. g., ate foods that are known to cause sickness (Rambam’s Commentary on the Mishnah).

For in this instance, he himself was the cause of his sickness.
Based on the Ramban and other Rishonim, the Shulchan Aruch (Ibid.) qualifies the Rambam’s ruling, explaining that if the person’s cure has a limited, defined cost, he must bear it himself. If, however, the cost is undefined, it must be borne by the others, even though his illness was due to his own negligence.
The Tur and the Ramah differ and maintain that when the person is negligent, the others are never liable. Moreover, even when he did not cause his sickness himself, if it has a definite cost, he must bear it alone.