Welcome, and I'm so sorry for your loss.
She looked near death in the video, and it's not suprising that she died soon after. Without a necropsy, it will be a mistery, except for finding external parasites, which might (or might not) have been a problem for her.
Chickens try very hard to act 'normal' until they just can't (just like cats!) so it can be very difficult to see early signs if illness.
Do look hard for mites or lice on the birds, at night with a flashlight, while they are roosting. Scaly leg mites are tough to find, and older hens will have 'rougher' leg scales than youngsters. A younger bird with rough scales is significant, or birds scratching their legs. With a small flock, vasoline on the legs several times works. I've never had to deal with them (fortunately!) and with a bigger flock like mine, treating legs ain't gonna happen. Ivermectin!
For other mites or lice, permethrin spray is easiest and very inexpensive (the concentrate), and the permethrin dust works too, but harder to use.
Hens can have different fatal internal difficulties, and generally a sick bird looks like a sick bird, regardless of the actual problem.
You can have fecals run at your veterinarian's, even if they don't treat birds, and only worm them if things turn up. Fenbendazole is the only approved product, although again, Ivermectin works too. Neither product kills all internal parasites, so finding out what, if anything is present matters.
How old are your birds? Many high egg producing hens live to be three, or maybe four years of age, sadly.
Mary
She looked near death in the video, and it's not suprising that she died soon after. Without a necropsy, it will be a mistery, except for finding external parasites, which might (or might not) have been a problem for her.
Chickens try very hard to act 'normal' until they just can't (just like cats!) so it can be very difficult to see early signs if illness.
Do look hard for mites or lice on the birds, at night with a flashlight, while they are roosting. Scaly leg mites are tough to find, and older hens will have 'rougher' leg scales than youngsters. A younger bird with rough scales is significant, or birds scratching their legs. With a small flock, vasoline on the legs several times works. I've never had to deal with them (fortunately!) and with a bigger flock like mine, treating legs ain't gonna happen. Ivermectin!
For other mites or lice, permethrin spray is easiest and very inexpensive (the concentrate), and the permethrin dust works too, but harder to use.
Hens can have different fatal internal difficulties, and generally a sick bird looks like a sick bird, regardless of the actual problem.
You can have fecals run at your veterinarian's, even if they don't treat birds, and only worm them if things turn up. Fenbendazole is the only approved product, although again, Ivermectin works too. Neither product kills all internal parasites, so finding out what, if anything is present matters.
How old are your birds? Many high egg producing hens live to be three, or maybe four years of age, sadly.
Mary