My local food pantry occasionally does that, but more often I'm the one ferrying it from the food pantry to Animal Control to prevent the other pantry volunteers from throwing it out. They'll sometimes put out stuff (like pet food and paper goods) that isn't in their usual the day they get it, but they don't have the storage to hang onto it very long, and they don't want to give the impression they can be relied on to have it.

Some places have a specific Pet Pantry (maybe this seven-year-old should talk to them about starting one if they don't!) and some food pantries do pet food regularly, it does vary a lot, but your odds are much better that it will actually get to a needy animal at the SPCA or at Animal Control.