Yup, duck eggs do have a protective layer--they're actually glossier than chicken eggs when first laid, especially if the hen sat on them for any length of time, because her natural oils rub off on them.
I was probably the one who posted about 6 months. They get eaten too fast in our house to actually test that theory, but I know that eggs in the stores are usually a few weeks old by the time you get them, and they've been washed & sanitized (which means their protective bloom is gone), and they still keep several weeks in the fridge at home. However, the nice thing about eggs is that they let you know if they've gone bad--just crack one open and you'll know. That is not true of salmonella infection, so I would certainly recommend *cooking* eggs that have been in the fridge a while, since salmonella is more likely to be present in large quantities in older eggs and you're not likely to be able to tell. But otherwise, if it smells good, it is good.
I'm also the one who posted about egg trays and ziploc baggies. We haven't had them in the freezer for long, but the eggs I tested by freezing overnight tasted great when thawed the next morning. Here is what I do:
* Buy a set of two ice cube trays at the dollar store, or use some that you already have.
* Crack a half dozen or a full dozen eggs into a bowl and lightly beat them to combine white & yolk and to reduce stiffness
* Pour half a dozen eggs into each tray (one dozen fits neatly into two trays)
* Freeze
* Place frozen egg cubes into a quart-sized ziploc baggie and return to freezer. One dozen fits neatly in one quart-sized bag.
* Be sure to label them because frozen eggs look a lot like frozen mango or peach--unpleasant surprise if you're making fruit pie!! lol
Enjoy!