My chickens and ducks are all pasture raised birds who eat local organic feed and whatever they find on my property. I've been selling their eggs to neighbors for $4/doz for chicken and $6/doz for duck. In the grocery store here I've seen the equivalent sell for $6/doz for chicken, and in the cities near to me the going rate is $5/doz for non-organic, large coop raised chickens. I've been taking my extra eggs every week to the homeless shelter. Since they're being used at the shelter, I have to clean the eggs, which I normally don't do with the average person so they can be kept on the counter. When asked for a value for the receipt I've been putting $13/flat of 30 since it's a mixture of duck and chicken eggs. Is it usually the local market value? The value I charge, which is comparatively low? I'm not quite sure how to value them for this. I haven't been taking into account the price of the flats or my time cleaning the eggs.