I also have a Khaki that always lays soft eggs and one that lays normal. They are both 1.5 years old and get the same everything as the three chickens. Oyster, layer feed, fresh water. They both laid like champs for the first year then one started the soft shells intermittently now it is every one. I have given calcium supplements (repti-calc powder for mealworms/crickets) and they did not seem to help. Not sure what is going on but I'm here to find out. I have heard that spinach can block calcium absorption but not about peas.