Feeding charts for Chihuahuas recommend giving them 1/2 to 1 1/2 cups of food a day depending on their age, size, and activity level. A tiny adult teacup Chihuahua, for example, would thrive on 1/2 cup, while a 5 pound adult Chihuahua may require up to 1 1/2 cups.
Chihuahua puppies require 1/4 to 1/2 cup of food per day divided into three to four meals. Because their bodies are growing and they’re very active, they require puppy food that’s formulated to meet their nutritional needs.
Senior Chihuahuas require less food because their metabolism is slowing down and they need less calories. You should feed them 1/4 cup of a senior dog food that fights the effects of aging three to four times a day.