First of all, we must note that not all single-parent families have problems. We should not stereotype or unfairly generalize. However, it is statistically true that single-parent families are more likely to include children who have problems such as poor nutrition and possibly poor hygiene. Again, this is not to say that all single-parent families have such problems, particularly not with hygiene. However, such families do face more problems than others.
To the extent that such problems exist, they exist largely for economic reasons. On average, single-parent families are more likely to be poor than two-parent families are. Poorer families are likely to have harder times having the time and money needed to maintain good nutrition and hygiene. A single parent will often not have as much money and may not be able to afford the most nutritious foods. Such a parent may also lack the time needed to do things like cooking nutritious meals. It is also possible that a single parent will not have enough time or money to keep the family home clean enough for idea hygiene. This means that a lack of time and money in single-parent families can make it harder for them to have good nutrition and even good hygiene.