First, I'm sooooooo sorry about your loss- it's very difficult when we care so much!
The paralysis is likely Marek's or perhaps a debilitating malabsorption issue that can be strictly due to a deficiency. I encourage you to send your bird to K-State so you can stop worrying. They do it for a $7 disposal fee and generally don't even bill that. A gross necropsy is all you need in order to know if it was Mareck's.
The form is
here and you just fill out the owner/breeder part, then Fill in the animal part with Chicken, Gallus, (breed sex age), then mark Whole Body, then Necropsy Only, and then fill out the info on what happened, how it progressed, and that you need to know if your other birds are at risk.
Write and highlight that you want to be contacted prior to necropsy completion, and they'll call you so you can tell them to go further with tests if they can't determine a cause. Make certain you put a number where you'll be easily reached right there, as well as at the top.
They are very nice and helpful.
Medicated feed is used at Beak House Hens only in the way of
chick starter with Amprolium- but it should be noted that that is only valuable if the chicks are exposed to soil.
Amprolium is a Thiamine blocker and interrupts the reproduction process of Coccidia. If the chick is in an environment where it isn't exposed to any dirt or natural materials like logs (I put a log or two in the brooder for them to pick at and hop on) they won't have exposure to the Coccidia and thus no need for the meds. There is benefit to giving them a hunk of sod in the brooder, etc.- that exposure WITH the Amprolium treated feed will give them the immunity or resistance to the Coccidia that they need over just a bit of time. It's not medication in that it treats the chicken, rather the medication in it is interrupting the parasite's ability to overwhelm the chick's intestinal system, thereby giving the chick's body a chance to learn to defend itself. A chick kept inside without Amprolium-treated feed and kept in a clean dry litter will have
some resistance if kept off of soil until 12-18 weeks, too, by virtue of size and being a more robust animal. It's easier to use the feed.
Regarding the
antibiotic-laced feed one can get, I don't use it. I don't allow birds to get ill with pathogenic illness and remain in my flock. In theory. It's never happened. I've had injuries and whatnot, but I send birds off to K-State to eliminate any doubt as to cause, and I practice very strict biosecurity. I'm full-on paranoid.
