I searched the forum and most say this is a feed issue. The chickens just started laying reliably. I have changed feed a few times. Mostly fed them Purina layena crumbles without the omega 3. I have tried Southern States which is a bit cheaper $14 for a 50pound bag. It has omega and marigolds.I am in North Carolina. The omega in the Sou. States feed does not seem overdone. It is their regular layer feed. The yolks come out darker and more orange on Southern States. At first I gave them some oyster shell in a separate feeder to get the harder shells. Has been removed and replaced with the granite grit. Change water often. Our eggs have a musty taste like dirt. They are in a coop with a run that does not move. I rake out the run regularly. I put wheat straw down sometimes in the run or sand. We have clay soil they have really torn up in the run. Cannot figure out what is putting the off taste into the eggs. We have two barred rocks, one australorp, an americauna, one buff orpington, a silver laced wyandotte and a gold laced. They seem healthy and happy. One of them likes to lay an egg in the run. The rest lay in the nest boxes. The only other variable is I insulated the roof of the coop with foil backed foam insulation. They decided to tear it apart as far up as they could reach. Seemed to like the shiny foil that I faced into the coop. It is gone now. I bet they ingested some. I really don't think it is a feed issue other than maybe the oyster shell. We give a little scratch. They like green grass pulled from the garden - no onions in the run or in what I give. So if anyone has some ideas, I would love to know. Tired of the earthy, musty tasting eggs.
I have tasted that same taste with very old eggs that I ingested once from a hidden nest...did the float test but they tasted bad anyway. If this were my flock I'd run them through some antibiotics just in case...but that is just me. It is best not to hand out antibiotics willy nilly but this would be my family's health, ingesting eggs and all. Here: http://edis.ifas.ufl.edu/ps020 http://www.thepoultrysite.com/publications/1/egg-quality-handbook/36/off-odours-and-flavours You might even consider calling your vet if you have a good relationship with one, to get a script for one they recommend.
Have they got clean nest boxes, one thing a lot of people don't realize is that egg shells are porous and will take in strong scents and tastes. Do you clean the eggs when you collect them? Dont give them any antibiotics, you should only give chickens antibiotics for respretory problems because if you just give them antibiotics for any problem that occurs chickens will become emune to them and they won't work when they are really needed. The insulation could possibly be the problem. Is it possible to let them out onto some grass or give them some greenery in their run like leaves from decideus trees, cabbage, kale, lettuce or other brassica plants. These will greatly improve your egg quality.
If not the feed, a couple other things... what are you doing with the eggs once you collect them, how long and where are you storing them, what do you wash them with, are your egg cartons fresh?