I remember hearing a PBS documentary make a claim that the babies of slaves on George Washington's Mount Vernon went naked in winter. I have been trying to verify, or even get a good citation, for this fact. (Any web reference to conditions of slaves owned by Founding Fathers also of interest).
The material aspects of life for slaves at Mount Vernon--things like their quarters, clothing, food--were very similar to the way things were done on other large plantations in 18th century Virginia (places like Monticello or Sabine Hall). In the case of infants, mothers at Mount Vernon were given a new blanket at the time of the birth and baby clothes of some type were provided, as well. For sources on slave life at Mount Vernon, we suggest the following:
Delano, Marfe Ferguson. Master George's People: George Washington, His Slaves, and His Revolutionary Transformation. Washington, DC: National Geographic, 2013.
The George Washington Digital Encyclopedia: http://www.mountvernon.org/encyclopedia#Slavery
Schwarz, Philip J., editor. Slavery at the Home of George Washington. Mount Vernon, VA: The Mount Vernon Ladies' Association, 2001.