Change of Egg Colour??

[Tartannik]

Three days ago I went to the nesting box to collect the eggs. I only have 3 chickens laying at the minute and they have started dropping off laying now that the nights are getting shorter. (I live in Scotland)
They are Black Rock X and all have been laying for well over a year and all lay brown eggs, one with spots on.
I also have 5 silkies who are 4 months old.
In the nesting box was a brown egg and a white egg. The white egg was rather large but the shell was quite soft. The last two white eggs have had a harder shell and look perfectly normal......BUT.........who is laying this white egg?
Tomorrow I am in the house all day so I shall be watching to see who is using the nest box ect but could the silkie be laying these big eggs????
I have a picture that I will post for you, it has a normal brown egg and the white eggs from the last two days, along side a 10p piece.
As far as i am led to believe, chickens just don't change the colour of their eggs, do they?????
Thank you in advance!!

 

[emys]

The brown pigment goes on last, and sometimes a brown egg layer will skip this part of the process and give you a white egg - especially when it is a soft shell egg as you described.

Maybe their oyster shell ran down to empty, or that hen is starting to molt and doesn't have the energy to lay at the same time.

 

[Tartannik]

Thank you for your answer Emys.
Maybe this is what is happening then although only the first egg was soft the other two seem to be perfect, I must try and catch what one it is!!

 

[tuesdays chicks]

Maybe 1 of your silky has a white egg gene

 

[Tartannik]

I had thought of that but I think it is much too big to be a silkie egg??

 

[tuesdays chicks]

They might be double yokers from a new layer