I also do not allow outside food for the allergy reason that others have said. Also, because I pride myself on making all home made foods and not serving processed foods, I wouldn't want to be feeding all my kids shephards pie for example and have one child having beans and chicken nuggets. While its the parents choice, it really puts the lunchtime routine at risk of becoming problematic if other kids suddenly decide to not eat the food provided because they are used to eating convenience foods at home and would prefer what the other child was being sent with.

I would always reinforce to the parents that their child will eat when they are hungry while letting them know there is always a settling in period and adjustment to a new setting and new meals and that you have never had a problem with children eating the meals you provide. I'd go on to say that the kids usually model each other and eat well as a group. Also, why not ask the parents outright why they send the food. If it really is because they fear their child won't eat what you feed them, why not ask them to give you the chance to try your food with them as it will teach them much better eating habits and make them more compliant and willing to try new things through adolesance. Maybe ask them to tell you some of their childs favourite meals so you can include them in your menu plan. If they are not meals you would serve your daycare children, then maybe you can come up with healthier versions. Its not that theirs a problem with the child, more just a way to reassure the parents that their child will settle in quickly to your meal plan as others have. I find the issue is typically with the parent's anxiety and fears when sending a child to daycare rather than with the child themselves. The kiddies are usually adaptable if you can be consistant and not give in to their power struggles when they try to refuse foods to get favourite snacks instead because that usually works at home with their parents.

This being said, some people don't see this situation as a problem so if you do not mind serving the food the parents send, and theres no issue with the other children not eating their meals as they want the other childs food, then I'd take full advantage of having less expense to pay out for these two children.