Shell less eggs being laid

[oapkeeper]

I have 3 hens, the older ex-batt is 3yrs old and for several weeks, since we got her 2 companions to replace the one that died from old age [8yrs] she has been laying shell less eggs, sometimes the membrane doesn't fully leave her body, it breaks and the egg goes into the nest box and gets eaten by whoever finds it first. I have been keeping hens for 10yrs now and have never had this problem before She is fine in herself. I thought she was going into moult as her feathers started to look a bit shabby. I have always given layers pellets along side the oyster shell with occasional treats. She is definitely the dominate hen. They free range my large garden. Any help appreciated.

 

[aart]

How long ago did this start?
Could be stress from the newbies and/or she'not eating her OS.
Could be she's just reaching the end her productivity.