Why Drumsticks are short

Sambar of South Indian food is delicious if it contains drumsticks as one of the ingredients. I tasted and enjoyed food with Drumstick sambar at Sambandar Alangulam of Madurai. I think the local drumsticks here are old variety. They appear stout but short in length. Why are they short? Any lack of natural fertilizer? Kindly discuss in the form of comments.