Many children from large families(6 and more children per family) are considered to be outsiders by other children because of their enormous family size and the factors that go with it. Children from large families are considered to be disadvantaged because they do not have the things that normal children have. Many of them are impoverished, lacking notebooks and other school essentials that their parents are unable to provide. They must depend upon their particular school to supply them with pencils, notebooks, &/or other school paraphernalia that they need.
They also stand out from other children because many of them do not have the proper clothes. Many of them have cast off clothing from churches & other charitable associations. Because of this, other children deride them, even avoid them. They also do not interface well with other children as they only feel comfortable interfacing only with their siblings. Many children from large families are suspicious of other children not their siblings. I have seen this among children from large families in elementary, junior high, & high school. Their suspicious attitude toward other children outside the family does not endear them to other children thus making them very unlikeable, even unpopular.
They also tend to be behavioral problems in the classroom as they were not disciplined by their parents, being left to raise themselves or their siblings. Teachers & other children note this, viewing such children to be problematic. They are also seen as uncultured by teachers & other children because they were not exposed to formative intellectual & cultural activities like other children are.
Many children from large families tend to indulge in deleterious, even delinquent activities because of their familial environment. They seem to emphasize physical, even street smarts instead of academic achievement. This attitude causes other children to see them in a negative light. Since they did not receive formative academic training by their parents, they are academically behind other children when they start school. Their disruptive classroom behavior is a cover up for their academic failings.