1 of 14 chicks slow feather growth

[Pinguella]

We have 14 chickens at 7 weeks of age. The mama has left them about 1 1/2 week ago and has started laying eggs again. She was not interested in the chicks any more and was quite aggressive so we placed her in a coop next to the chickens.

The chicks seem fine, grow fast and all of them developes at about the same rate except one. 13 of them have full feathers all over, but one has not grown feathers at the top of its wings and a part of the back yet, he/she still has the fluff instead of feathers. :/
The chick has no marks of pecking and we have not seen any of the other chicks pecking on him/her or any of the others.

Is it normal that a chick can get its feathers developed this much later than the others or is this a sign that something is wrong with the chick?

There are no sign of any external parasites, we have put in a smoke tablet just to be sure.
They get a starter feed and we have given them additional vitamines mixed in water.

 

[oldhenlikesdogs]

Some rooster chicks can take forever to finish feathering, I would bet it's a little rooster.

 

[Pinguella]

Oh. :/ this one does not show any other signs of beeing a rooster, since the comb is a lot more yellow than some of the others, but the chickens are a mix of sussex and wyandotte so sexing them is close to impossible, for us at least since we are only 1 1/2 years into keeping chickens.

Fingers crossed its not 14 roos, last time we bought chicks we got 4 out of 5 roos (sussex ) and the 2 wyandottes that was gauaranteed hens from seller turned out to bee roos. We already had 2 mini roos, so at that point we had 8 roosters and one hen

 

[azygous]

The lack of feathering on your questionable chick does signal a possible cockerel. The comb should be showing a hint of orange around the base if it's a boy. Look for red spots of flesh under its lower beak, indicating wattle buds.

Compare its legs and feet with the others. A cockerel by this age will have noticeably larger feet and thicker legs. Temperament may be a tad more impulsive and hyper than the pullets, too.

If you only get one cockerel out of fourteen, you are skating close to the miraculous. I've been getting a 30% cockerel rate this year, and feel downright cursed.

 

[Pinguella]

No, I got others showing signs of cockerel, almost sure at least 5 of the others are cockerels but they have more red comb, large feet and well developed wattles already. Are hens with wattles getting them later on? The sussex mom also has red wattles but smaller of course, just can't remember when they grew out compared to the roos.
All the chicks have single comb from the Wyandotte father, so it's not easy to see the difference since there is not much comb on any of them yet.
The 5 that looks like roos have thicker feet, more red on comb and seem to have grown a bit bigger than the others. I just hope we get a few hens out of the fourteen.

At this time all of our free range hens have started laying their eggs in an unknown location at the farm so for the first time in a year we have been all out of eggs

I guess this is a possible stink bomb in time but our searches have given no result this far. So starting today they are not so free range any more.