There are two things that are factors. As I recall, when Ino was broadcasting for Shikamaru... significant numbers of Shinobi had already died.
Furthermore, her recent efforts were done with the aid of Naruto's Chakra Cloak (except possibly for Shikamaru's first talk).
Now, this doesn't 100% mean she has low levels of chakra, nor does it mean she cannot have high levels of chakra.
She most likely has a regular to fair level of chakra, and a good amount of control. Factoring the declining numbers of the Alliance... this makes her even more capable of sending Alliance Wide Messages.