She's way too thin =|

Rib-cages aren't down THAT low, are they?

This picture seems off in so many ways.

her breasts look off as well...

Extreme malnourishment does things to your figure. Especially when one of the largest fat stores of the female body are the breasts, and fat can be split up for glucose to stay alive.

Assuming youkai metabolism to be equivalent to human, that's a solid 3-4-5 weeks with no or very little food.