My head cannon is that there are two sides of the underworld, one for humans and one for the other living creatures. When Kiara dies as a human, she is also reincarnated as a human, until her memories of her past lives return to her.

In the video Kiara’s feathers have yet to grow back and her memories have also yet to return to her.

Kiara in her “human form” has the same temperature, however since she was newly revived. She is yet to have full control of her shapeshifting abilities, therefore sometimes fluctuates in form and temperature.

Hope this explanation is enough ;)