Baby Chin Not Growing... PLEASE HELP!

I got my Sassy at 10 weeks old and she is now 5 months. She hasn't seemed to have grown much and is half the size of all my other full grown chins. I do notice she isn't the size of other 5 month old chins either. There is a smaller breed of chinchillas, the costina. She does have shorter fur than my others.

Quote:

The Costina is the smallest size of the chinchillidae family... They have short fur, which is not as compact as the Lanigera or Brevicaudata breeds due to them not needing the extra warmth living in the lowest regions of the Andes Mountains of 3,000 feet about sea level. Costinas have a 'pointy' head shape leading to a 'rat-like' nose and have longer ears and tail than the other breeds. They are slightly more 'highly-strung' than their cousins and rarely found within the pet industry.

This is where i read it :

http://ift.tt/1C9hAqK





I feed her oxbow brand pellets and alfalfa to try to get her to grow but she simply isn't. I was even wondering if there may be something wrong. Does anyone know?



You can see pictures of her here:



~http://ift.tt/1y7VL5Y



~http://ift.tt/1C9hAqQ