The Price to Pay

The Gemara in Kiddushin (17a) discusses the situation of an eved Ivri, an indentured servant, who became ill. His boss contracted with him for six years of labor. However, he was ill for two years. Can his boss demand a refund for those two years where he just stayed in bed all day? The Gemara answers unequivocally in the negative. It is the boss’s bad mazal, and he must absorb the loss.
Tosfos comment that there are those who equate the situation in the Gemara to that of a rebbe who was hired to teach children and then fell ill. They would argue that if the rebbe was sick for less than half of his contracted term, then the school that hired him must pay his full salary. Since the rebbe cannot be faulted for becoming ill, the yeshiva must absorb the loss.
The Gemara in Bava Metzia (77a) discusses a day laborer who fell ill at midday. Tosfos say that the Gemara implies that he does not get his full daily salary, but neither is he penalized. For the half-day that he worked, he gets paid; the day laborer will not get paid for the half-day that he was legitimately AWOL. Regarding this issue, a rebbe should be treated the same as a day laborer: He should get paid for the time he taught, but if he was sick for a significant period of time, his pay should be docked.