Hi, We have a variety of chickens that we have had since chicks and they all started laying about a month ago. During the night two of them layed soft shelled eggs. This happened a few weeks ago too? Any idea why this might have happened? Usually my girls egg shells are very hard. We frequently throw some to our dogs and they don't even break, you have to tap it with your foot to get it to break. Is this normal or is something missing from their diet? Thanks in advance for your help. Jenny.