Why did the parents find it difficult to feed their children in "The Boy Who Drew Cats"?

The Japanese fairy tale "The Boy Who Drew Cats" is the story of a child trying to find a place to fit in. At the very beginning of the story, the child lives with his family, but that quickly changes. The family lives in a small village and they are farmers. Because of this, they are not rich and barely have enough to get by.
Being a farmer is very difficult. Life itself depends on the crops growing well, yielding enough, and being harvested on time, and people still have to tighten their belts to make do. When living on a small farm, everybody has to contribute in some way. There are always chores and work to be done. From an early age, children in this setting understand that they play a very significant role in the life and survival of a family farm.
The couple has many children, which puts a drain on the few resources they have. An older teenage son is very strong and sturdy and is able to help his father with the farm work. There are also a number of daughters who help with their mother's work. The youngest child, another boy, is not able to help with the farm work. He is very small and weak, and the family is told that he will never grow to be big enough to help on the farm. He is, however, very intelligent. Because of this, his parents decide to take him to a temple so he can become a priest. This will help him to find something more suited to his abilities, and it will be one less mouth that the family has to try to feed.