I know that we are not allowed to derive benefit from chometz during Pesach, and that this prohibition extends to feeding our pets food containing chometz. (Source: http://cor.ca/view-515-pet-food-on-passover-and-throughout-the-yearhtml.htm) Would having chometz in an outdoor birdfeeder on our property count as a violation, given that the animals are not our pets, that the "feeding" is completely passive, and that there may be an ethical mandate to continue feeding birds one has already fed for a long time? (The last point insofar as we are not necessarily feeding them to derive benefit for ourselves.)
Tangentially related: Badikas Chamatz in courtyards of cities today