I have five month old female pekin duck. She began laying a month ago perfect eggs. Two weeks ago she started to lay flat sided eggs and then a few soft shell eggs. She now has not layed for a few days, at least I have found any they do free range during the day. I have noticed that her bill is getting pale as well. I started to leave oyster shells out but I am not sure if she is eating them or not. She houses with a few older chickens and lots of two month old chickens. Any advice is welcome because my husband absolutely loves her.