This is the first time posting and couldn't figure out where it should go...

I have:

2 bantam cochin mixes ( Chickadee & Crackerjack) that lay white/pinkish eggs

2 red comets - ( Red ) one that hasn't laid a viable egg since July 2014 and no egg since Sept 2014 (she is past her laying stage and her eggs were size of coke can) and ( Purple ) other is laying normally

1 easter egger ( Gertrude ) that lays blue eggs.

Now the odd thing is on occasion I get a deep mauve/brown egg that is same size as Gertrudes blue eggs.

The only thing I can guess is that they are hers and they seem to show up anytime there is a disruption in her routine like not getting to free range daily and as of today being housed in my house ( overnight last night and again tonight ) due to the coop not being able to withstand -5 degree weather.

Anybody have any ideas as to where these eggs are coming from?