Help! My eggs won't peel

Because we have an overabundance of duck eggs at the moment, my husband cooked up a dozen of the 5 or so day old eggs. These were the oldest eggs that we had. He cooked them the way he found on the internet (I was at work) and put them in cold water. He left them for about 1/2 an hour then tried to peel them and made a huge mess (whites sticking to shells and coming off in big chunks). Now what to do? Throw them out and start again? What went wrong? Any advice to get the perfect egg?

Throw some eggs to the back of the fridge...forget about em. Then find them a few weeks from now and try again
New eggs are never gonna peel easily. Or just poach some eggs. Similair to a hard boiled egg just slimier haha.

I read putting baking soda in the water helps. This does nothing for your current eggs, but might help the next batch.

I put a little bit of vinegar in the boiling water, seems to work so far!

Hit it with a knife in half and scoop it empty, that's how we eat our eggs

leave a dozen in the back of your fridge for about 3 weeks that should do it

I agree with Anna thats what we do I send eggs for kids lunches all the time and thats how I do it. I smack it and open it most of the way then send a spoon along with them I've had plenty of hard boiled eggs in my life but I have never peeled one