[Chihuahuas] feeding amounts

[Randi]

I have two 4 pound chi’s and the nutro small breed says to feed 1/3 cup a day. 
So I half that for the two feedings. One is very happy with that but the other 
always acts starved. Do you think 1/3 cup is to little of an amount thanks. And 
sorry for the two sizes of letters this computer is wacko
Randi