curious chickee, there are a ton of things that look like mareks. Read this:
https://www.backyardchickens.com/a/the-great-big-giant-mareks-disease-faq
If it is mareks, and you will only know by a confirmed vet diagnosis - it is too late to vacinate. Your flock is exposed unless you have separate quarters, separate by a minimum of 100 feet, and have practiced incredible biosecurity.
Take an ill chicken or a dead chick to your university vet pathology lab - your local vet can make the arrangements, or you can. sometimes cheaper if you do it yourself. body has to be kept cool, ec. that way they will do a necropsy and confirm whether it is or isn't mareks. silkies seem more prone to mareks, but that is just my thoughts based on reading, and I could be wrong.
It also could be a vitamin deficiency - you might want to look into that. just search vitamin deficiency here on byc.
personally, I would start them on a vitamin supplement - avail at your local feed store, asap. just in case.....couldn't hurt and might help. Also, try feeding beef or chicken liver - easier to slice if it is frozen. tiny shreds or tidbits is what you are looking for.
Keep us posted, and also consider posting in the emergency forum for fast responses. Like all responses on the internet, you have to use your own judgement.
