MAKE SURE THEY HAVE OYSTER SHELL/GRIT! Soft-shelled eggs can be a sign that hey are not getting enough calcium.
If there are no other outside facctors--sick, molting, mites, weather--then they may be going through a dryer period. If it's just a day-to-day issue then that seems to be pretty normal. Out of my small flock I can expect 2-3 eggs a day typically (not all hens lay every day--this is normal and healthy). Last week I had 6 in one day. Today only two so far. This does not mean anything is wrong with them.
However, if you notice a drop in egg production all at once, this could be a sign that something's wrong.
Check for the common factors: is the feed clean, good quality and the right kind? How about their drinking water? Is it overly hot/cold? Could they have mites? How do their crops look/feel? Is the coop clean?
Look carefully for signs of illness--there are many online resources for common signs of sickness in poultry--and quarantine/treat appropriately.
Remember that chickens are hardy but can take a while to bounce back. If there was a sudden cold snap last weekend, or it hit a 100 for the first time this year (like it did here in AZ), don't expect your chickens to be back to normal today. Same with illness or broodiness: they take a bit to get over it. If they are ill or focusing all of their energy on staying warm/cooling off, they won't lay many eggs. Eggs take work and expendable energy!
Check all your bases, and keep an eye on them. And check your yard: they may also be hiding nests from you--it is spring afterall.
