Without seeing its face I can't tell what the animal is, but the crow is plucking its tail fur,

[tblue37]

probably to line a sleeping spot. Could be a deer?

Link to tweet

[3catwoman3]

1. Some sort of deer...

...or antelope? It looks the same as the one higher up in the picture.

[2naSalit]

2. They look like a couple white-tail...

Sad scene, they are so miserable in captivity that the raven plucking its tail isn't even a concern. That animal won't last much longer in that place.

[Kali]

5. I am not so sure about that

they look pretty healthy to me, and if the raven is nest building it is probably spring - which means the deer are shedding/molting - and the body coat looks exactly like that to me. I bet the tail fur is pretty loose.

deer like handouts and will adapt to being around people too well, actually. they might not even be captive, other than existing in some kind of park where a lot of people go.

[Midnight Writer]

3. I clipped my dog's fur in the back yard. Birds swarmed picking up the fluff.

[sl8]

4. Seems to be one of the Nara (Japan) deer:

https://www.msn.com/en-gb/video/viral/clever-crow-pulls-off-fur-from-deers-bottom-to-use-in-its-nest-in-japan/vi-AAKpdmi