"Unnamed female deer" is not an official name yet. It may have been referenced in the storyline as such, but has not been officially named. Alternatively, it may be a name popular among fans, but has no official basis.
As seen in "Pups Save the Deer", she and her mate were stuck in slippery ice near Rock Island. She was later rescued by Ryder, the PAW Patrol and Jake, giving her carrots and later was carried back to safe grounds through Ryder's ATV.
As a mother, she is worried when her child is in danger. This is shown in "Pups Save the Deer", where the deer parents waited until their child was rescued safe and sound.
Unnamed female deer is light brown in appearance. She takes on the appearance of a typical doe.