Mommy gets a break?
What about Mommy?
Maybe have them prepare and choose already packaged foods to put in a container for the next day to make things easier for Mommy?
How about they do it some days, you do it other days?
How about by week?
Just some thoughts.
I am by NO means a subscriber in teaching children that Mommy loves you SO much that she is GOING to DO all this FOR YOU at HER EXPENSE thereby YOU don't LEARN RESPONSIBILITY IN ALL AREAS.
A sidenote might be to DO the lunches yourself while addressing the other new chores and wait until they are better established before adding something else to their agenda.
I DO however surprise them by getting up early and packing it before they have to, or the night before, or enclosing a note or small toy (if school permits) to make them smile. Even a handmade coupon for some one on one time (fold it so they don't have to let the other kids see). I feel that letting them have the experience of doing for themselves and THEN having Mommy do it for them out of love will garner a lot more love and appreciation for What Mommy Does for everyone!
*~"After all...tomorrow is another day!"~* -- Scarlett O'Hara - "Gone With the Wind" (1939)