https://www.backyardchickens.com/threads/is-this-isbar-silverudds-blue-eggs-or-did-i-recieve-mix-eggs.1096526/
A thread I found regarding the egg color.
Thats a good possibility. The one that lays the tan colored eggs was hatched from Foxfire. Along with two black Isbars and a white (technically a splash, but has only one black mark). The one that lays tan eggs and the almost solid white one are not breeding quality. If we do choose to separate...
I thought the same thing until this little pastel tan one came out. I looked it up and sometimes they do lay a pastel tan colored egg surprisingly.
That’s probably not a desired trait, but they taste the same :D