Weird bump on Eggs

[gritsar]

Some hens can have calcium absorption problems or other issues in the egg laying dept. I wouldn't eat an egg where the shell wasn't intact, but otherwise I keep them for my family's consumption; just don't sell them.

 

[CapellaFarm]

Is it possible that they're not getting enough calcium? I noticed this during the winter and found my husband hadn't given them oyster shells for a while. It also sounds like she might be getting older.