Okay I'm seriously getting a complex now about dishwashers. Over the last few years we have had 2 bosch dishwashers brand new break and be completely unfixable after multiple attempts by the warranty people. So this last time we decided to get something other then a bosch, and went w/ a GE, which had good reviews, and now the kitchen is a lake (well maybe a pond) and one of the hoses underneath the machine is leaking at a manufacturer joint!!!!!!
At 4 months I would offer oyster shell for sure. As long as they have oyster shell you wouldn't HAVE to switch to a layer feed if you didn't want to. IMO oyster shell is ness. w/ or w/o layer food, each chicken is individual and some need more or less, Ca, that way they can self regulate.
Sorry about your loss of the chickens, critterwoman I don't have any extra brown layers