It's normal. Chicks grow faster than their feathers grow in. The down that they are born with stops completely covering them in just a week or two. Basically, they only have the down that they are born with until their feathers grow in. The chick grows in size faster than the feathers can, leaving small bald patches for a couple weeks.
I also have other breeds that were hatched the same day but non of them have that lump and have all of there feathers already just not my 2vlack sex links. They both have missing patches of feathers and a lump on the side if there neck lower next just above there wing joint
This is my next question this on on the runt of the two black sex links this chick has had its poop stuck to it. It riped the poop off of its self and now the but hole is swollen and I haven't seen it poop yet is that normal. After it did it I thought it was a goner the chick couldn't walk or stand but now it's been 2 hours and it's standing.. but I still am yet to see it poop
That is called a pasty vent. The runny poo will 'seal' the vent shut. It can kill a chick. You should check young chicks vents a couple times a day. If one is pasted up, gently clear the vent. Warm water helps with this. Pasty vents are usually a caused by stressed chicks. Keeping the brooder in a quite, darker place helps avoid it. Make sure the chicks are kept warm enough and make sure the one with the pasty vent is getting plenty to drink. Dipping the beak in water will force the chick to drink.