Most veterinarians will recommend the following schedule for feeding puppies six weeks or older (after being weaned)
Six weeks to three months - four meals a day
Three months to six months - three meals a day
Six months to one year - two meals a day
One year and up - one to three meals a day
While this is the standard for most dogs, many Chihuahuas prefer to eat several small meals throughout the day, regardless of age.
Small size dry dog food is fine for your dog, although the preferred choice would be dry food mixed with canned food. Feeding your Chihuahua canned food only is not a good idea. Their digestive tract can't process canned food alone, which may result in diarrhea and dehydration. Several Chihuahua owners mix dry dog food with a small amount of white rice and cooked, diced chicken.