I have 3 Buff Orpingtons I bought them from the local 4H auction and they were 22 weeks in October. Anyway to make a long story short they have been laying wonderfully..3 light brown eggs a day..today there was one egg that was mostly white and had a "lump" on it..maybe a calcium deposit.Can someone tell me what might cause this..the only thing different I did was sprinkle Diatomaceous Earth..it was food grade..could this be the cause? Possibly she ingested some and the other two did not? Thank you for any help!!