Mechanism for mechanical timer

Hello everyone,

My wife and I both feed the dog, but we're never sure whether the other's already done it or not.  (the food disappears pretty quickly)  I'd like to build a track with a slider that takes about 10 hours to slide from 'fed' at the top to 'not fed', and make it so that the slider is easy to slide back to the top.

What immediately comes to mind is a counter weight escapement mechanism, but I though I'd hit up the brain trust to make sure there wasn't a simpler way to pull this off.  (I could also envision a timer chip hooked to a mechanical release, but I'd prefer to stay wholly mechanical for this one.)

Many thanks!