I have read in numerous bird-related publications NOT to use regular bleach
as the residue can negatively impact the birds. Hydrogen peroxide is the
recommended alternative.

If the neighbors are receptive, I'd be inclined to meet them, explain what
is happening as a result of their feeding (they most likely have no idea)
and ask them to provide water on their property for the crows that they are
feeding. If they are willing to do that, it should take care of the
problem.

Carol Riddell
Edmonds