The Ewells are a generationally poor family. Atticus explains to Scout,
"Atticus said that Ewells had been a disgrace to Maycomb for three generations. None of them had done an honest day of work in his recollection........they were people but they lived like animals.....'There are ways of keeping them in school by force, but it's silly to force people like the Ewells into a new environment.'" (pg 30)
Therefore they lived off of welfare. Bob Ewell is known for spending his relief check on liquor while his children are crying from hunger. The mother is dead, and so Mayella has to take care of all the other children. The society turns its head when the Ewells hunt out of season because at least the children will be fed, Atticus says,
"I don't know of any landowner around here who begrudges those children any game that their father can hit." (pg 31)
Later, during the trial, Scout explains the Ewells.
"Every town the size of Maycomb had families like the Ewells. No economic fluctuations changed their status--- people like the Ewells lived as guests of the county in prosperity as well as in the depths of a depression. No truant officer could keep their numerous offspring in school; no public health officer could free them from congenital defects, various worms, and the diseases indigenous to filthy surroundings." (170)
Socially they were outcasts, but the town understood that they were part of a society of a town that size. No one knows how many children Bob Ewell has. They survive by going through items at the dump every day.
"The varmints had a lean time of it, for the Ewells gave the dump a thorough gleaning every day, and the fruits of their industry (those that were not eaten) made the plot of ground around the cabin look like the playhouse of an insane child...." (pg 170)
The society basically ignored them. Nobody came by to check on them, and no one came to visit except at Christmas when "the church delivered baskets". (pg 171)