In reviewing the 1940 census enumerations for my Ufkes cousins in Hancock County, Illinois, I found an entry for a Henry Ufkes, married and just starting his family. The age was inconsistent with the known Henrys in the family at that time and there was no child in the family with the name of Henry’s child. Further research revealed that the census taker simply wrote down the wrong last name and substituted the last name of Fecht with Ufkes. There were many families with both last names in the township.
Is it possible the census taker got mixed up when writing your family’s census entry? 
2 Responses
I read that the census taker did not always speak with the head of the household, but with whomever answered the door – sometimes a child or even a neighbor.
That’s true. In 1940 the enumerator was supposed to indicate with whom he or she spoke. In this specific case I think the enumerator very possibly got mixed up as there were a few last names that were shared by quite a few families. Someone unfamiliar with the local residents could easily have gotten them confused.