So much for co-brooding. Now I am down to only one of the Mottled AM chick.

The Cochin Banty has had only darker colored chicks under her most of the time and the experienced Wyandotte has had the mottled chicks. I went out this morning to feed and check on the chicks around 7 this morning. There should have been 10 and I was only counting 8. I moved the cat little box they have been in and looked thru the bedding. I found one dead mottled chick in there and the another dead one near the from and just outside the box. I thought maybe they had just gotten chilled so I rearranged the area and brought the bodies in. I went back out to collect eggs about noon and found another mottled chick in it's death throws on the floor of the broody coop. I couldn't save it.
The Cochin broody has been pretty aggressive with me, but only to protect the dark chicks. I had seen her peck a bit at the mottled ones but not in a super aggressive way. I know the Wyandotte is fine with mixed colors because she has raised them before. I decided I will not chance the Cochin harming the last mottled chick. She is now out of the broody coop and the Wyandotte will raise the chicks alone. The Cochin was, needless to say, not a happy camper and was squawking up a storm. She got a dunked a couple of times and has calmed down. The eggs have all bee laid for the day so she will not be allowed into the pen until bed time and then the lower door to the coop will be closed for the night so she can't get close to the broody coop/chicks.
I am so frustrated I wanted to wring her little neck! Naturally it would be only the mottled chicks that would die. I now have 1 OE, 1 Mottled and 5 Marans chicks.