Odd post birth stuff attached to chick after hatching

[Blue Legs]

So, first batch of eggs hatching. Everyone except this one seems uniform in color and how they appeared immediately upon hatching was uniform as well. They are all bresse. This one looks very different.
1) he is grey in feather coloration and purplish body. All other chicks are yellow feathered with pinkish bodies
2) it has something attached to it. It seems like an umbilical attached to a mass is some sort. The cord has now dried.

It was brought to my attention that this may be seriously abnormal. Pictures are attached, unsure how to proceed. Chick is still in incubator with other hatching chicks, 99.5°f, 70%rh. Hatched less than 3 hours ago

 

[Blue Legs]

Current pics. None of the other birds are anything like this.

 

[Blue Legs]

The post birth mass has now detached. Chick seems to be as healthy as all the others

 

[Blue Legs]

This chick is still alive but has not yet opened it's eyes. Unsure what to think at this time. All other birds are uniform in color and disposition. It also complained loudly when placed into the brooder where all the other chicks are happily doing chicken stuff. Due to this I have allowed it to remain in the incubator where is seems happy. Is this a bird that should be culled? Is it a little underdeveloped? Need special care?

 

[Jmiller89]

Anyone have any idea what’s going on with this chick?

 

[JacinLarkwell]

It's fine. Sometimes chicks hatch with stings of good on it. What breed are they all supposed to be?