It is not unknown for a family to evade the census, or for census pages to be missing or damaged.
It is worth remembering, the census images are themselves transcriptions made my the enumerator from the schedule to the volume. It is quite possible that a family could be missed out entirely in the transcription, or they may have been transcribed under an entirely different name, I spent days searching for a family, only to discover they were all there under the name of the family in the previous household, the enumerator had forgotten to change the surname.
Jebber