He was only 4 foot 6 and 87 pounds at age 15 when he died.
For reference: As the average weight of an fifteen year old male is 128 pounds this puts him just below the third percentile (very underweight) – the average height for a male kid that age is 67 inches or 5 feet 7 inches tall. Obviously Jay wasn’t close to either of these averages.
So … he was tiny. He was a very smol bird. Still recovering from the effects of malnutrition.