I actually think she's okay. No fat on her but she's fairly meaty. I've seen older does look like this in the late summer.
Her big belly is probably pulling her skin tight enough to make her ribs look a bit startling... but she's a long way from emaciated. I bet once her hair grows out a bit, she'll look fine.

She is alert,attentive,eating and bright eyed. She is in her summer coat. Sure, she is a little thin, but It is not unusual to see the ribs on deer, especially does who are/have been being nursed, this time of year.

Ive seen does this time of year, especially in places where theres not good mast production, or crops (i.e. pine plantations around this area) look like with two fawns nursing her to death. The ones I saw eventually popped the titty out of the fawns mouth and fattened back up.