What does volunteering at a food bank have to do with it? The ones who get to the food banks, or get the WIC coupons, or have meals delivered are doing ok. It's the ones who for whatever reason don't realize that there's really no way (at least in Washington state and Maryland, dunno about Portland) a child should not have enough to eat.
Qualifications for WIC (up to 5 y/o with income requirements). If it's just a single mom and one child (most limiting scenario), you have to make less than $2300/mo. More kids (or a two-parent home), higher income floor.
Free or reduced-rate school lunches. Limiting income requirement (single mom and one child) is 20k, two-parent or single parent with 2 kids is 28k.
Before and after-school snacks at daycares(up to age 12) Also income-based, but it sucks if you are paying for a daycare that's already a big drain on income. But food is there.
Food stamps. Again, limiting case you'd get $367
a month in food stamps for an income less than ~20k.
If you're still hungry and have exhausted those possibilities, I've worked with each of these institutions:
West Seattle Food Bank
Kent Food Bank
CityTeam Mission
Riva Trace Baptist Church
It isn't that there aren't any resources (especially for children) to get food from, but educating people about where to go. I don't know that someone who doesn't have enough to eat will be able to watch Sesame Street (in English!) and then be able to find out about the resources in their community. But it's a decent try, I guess.