“Did families just avoid talking about slavery in the years before the Civil War?”

In the North, the Republican Party was founded in 1854 to prevent chattel slavery from expanding in the USA, and Uncle Tom's Cabin was the best selling novel of the entire 19th Century, so someone was talking about it. In the Antebellum South the slaves were right there in the house and a major source of wealth, so they were certainly talked about all the time. The slave owners generally weren't ashamed or troubled by what they were doing since it was perfectly legal and socially acceptable. When people up North suggested that the slaves be freed without consulting or compensating the slave owners, that conversation down South took the dark turn to rebellion.

But it is important to remember that women couldn't vote and weren't expected to be conversant in the ways of the World beyond the kitchen in the mid-19th Century, even though one of them had written Uncle Tom's Cabin and some of the best known abolitionists were women.