Feels sort of silly to ask, but given at least some slave-owners held the hypocritical stance that part of the reason for slavery was to impart Christianity, did the owners give Christmas or other holidays free from work?
While it can be dangerous to generalize about American slavery, because the institution changed and varied so much over time and space, it was a common tradition for masters to "give" their slaves "time off" around Christmas. On those days, the slaves would not be expected to work, and typical restrictions on the free movement of slaves (e.g., from one local plantation to another) were relaxed or eliminated entirely.
In his 1845 memoir, Frederick Douglass described this tradition in the plantation country of southern Maryland thusly:
The days between Christmas and New Year's day are allowed as holidays; and, accordingly, we were not required to perform any labor, more than to feed and take care of the stock. This time we regarded as our own, by the grace of our masters; and we therefore used or abused it nearly as we pleased. Those of us who had families at a distance, were generally allowed to spend the whole six days in their society. This time, however, was spent in various ways. The staid, sober, thinking and industrious ones of our number would employ themselves in making corn-brooms, mats, horse-collars, and baskets; and another class of us would spend the time in hunting opossums, hares, and coons. But by far the larger part engaged in such sports and merriments as playing ball, wrestling, running foot-races, fiddling, dancing, and drinking whisky; and this latter mode of spending the time was by far the most agreeable to the feelings of our masters. A slave who would work during the holidays was considered by our masters as scarcely deserving them. He was regarded as one who rejected the favor of his master. It was deemed a disgrace not to get drunk at Christmas; and he was regarded as lazy indeed, who had not provided himself with the necessary means, during the year, to get whisky enough to last him through Christmas.
Douglass alluded to the fact that many slaves had fractured families, with husbands, wives, parents, and children living apart from one another (though in the same region). For such people, the holidays were a precious opportunity - perhaps their only such opportunity during the year - to reunite temporarily.
The Christmas holidays could be an opportunity to catch up on neglected personal affairs. Henry Bibb, a Kentucky slave, used one Christmas holiday to get married. The couple then spent the remainder of the holidays "in matrimonial visiting among our friends, while it should have been spent in running away to Canada, for our liberty."
Solomon Northup's 1853 memoir Twelve Years a Slave provided a similarly "festive" account from the Louisiana plantation on which he was held in bondage in the 1840s and 1850s:
The only respite from constant labor the slave has through the whole year, is during the Christmas holidays. [Northup's master Edwin] Epps allowed us three — others allow four, five and six days, according to the measure of their generosity. It is the only time to which they look forward with any interest or pleasure. They are glad when night comes, not only because it brings them a few hours repose, but because it brings them one day nearer Christmas. It is hailed with equal delight by the old and the young; even Uncle Abram ceases to glorify Andrew Jackson, and Patsey forgets her many sorrows amid the general hilarity of the holidays. It is the time of feasting, and frolicking, and fiddling — the carnival season with the children of bondage. They are the only days when they are allowed a little restricted liberty, and heartily indeed do they enjoy it.
Northup further described a large annual Christmas dinner and dance put on for the local slaves by the local slaveholders - with the plantation owners, including Northup's own master, rotating responsibility for hosting. This account is made all the more striking by the reader's knowledge that Northup's master was, even by the standards of plantation slaveholders, an unusually cruel man.
Northup also described how some slaves would remain home during the holidays and continue to work, "in which case they are paid for it."
Of course, this was not a time of unalloyed joy, recreation, and relaxation for enslaved people. Many greeted the holidays with anger, or even fear. Douglass's analysis of this practice is cutting and critical. He understood the holiday allowance not as an act of Christian charity or kindness on the part of the masters, but as a tool of control, cruelly deployed by shrewd cynics:
The holidays are part and parcel of the gross fraud, wrong, and inhumanity of slavery. They are professedly a custom established by the benevolence of the slaveholders; but I undertake to say, it is the result of selfishness, and one of the grossest frauds committed upon the down-trodden slave. They do not give the slaves this time because they would not like to have their work during its continuance, but because they know it would be unsafe to deprive them of it. This will be seen by the fact, that the slaveholders like to have their slaves spend those days just in such a manner as to make them as glad of their ending as of their beginning. Their object seems to be, to disgust their slaves with freedom, by plunging them into the lowest depths of dissipation. For instance, the slaveholders not only like to see the slave drink of his own accord, but will adopt various plans to make him drunk. One plan is, to make bets on their slaves, as to who can drink the most whisky without getting drunk; and in this way they succeed in getting whole multitudes to drink to excess. Thus, when the slave asks for virtuous freedom, the cunning slaveholder, knowing his ignorance, cheats him with a dose of vicious dissipation, artfully labelled with the name of liberty. The most of us used to drink it down, and the result was just what might be supposed: many of us were led to think that there was little to choose between liberty and slavery. We felt, and very properly too, that we had almost as well be slaves to man as to rum. So, when the holidays ended, we staggered up from the filth of our wallowing, took a long breath, and marched to the field,-- feeling, upon the whole, rather glad to go, from what our master had deceived us into a belief was freedom, back to the arms of slavery.
In a later memoir (published in 1855), Douglass elaborated:
It was not what we had taken it to be, nor what it might have been, had it not been abused by us. It was about as well to be a slave to master, as to be a slave to rum and whisky.
For other slaves, the joy of the holiday was snuffed by the dread of what came after it - New Year's Day, or "Hiring Day" as it was called in the slave economy. On Hiring Day, slaves were often bought, sold, and rented. Annual contracts for the hiring-out of slaves would often begin on on 1 January. This meant that the first days of the new year were a time of abject terror and rage for those slaves whose families were torn apart. "Were it not that hiring day is near at hand, and many families are fearfully looking forward to the probability of separation in a few days," wrote Harriet Jacobs in her 1861 memoir Incidents in the Life of a Slave Girl, "Christmas might be a happy season for the poor slaves."