These two pages from the 1850 census include William and his six sons.
"United States Census, 1850," database with images, FamilySearch (https://familysearch.org/ark:/61903/3:1:S3HT-DRLG-R8?cc=1401638&wc=95R3-79N%3A1031325101%2C1032889301%2C1032889302 : 9 April 2016), Kentucky > Breathitt > Breathitt county, part of > images 20 and 21 of 89; citing NARA microfilm publication M432 (Washington, D.C.: National Archives and Records Administration, n.d.).