Just my thoughts for what they are worth
Stick with breeders you know or who are recommended, there are a lot of very iffy breeders out there and a lot of the Chi's being sold now are just bred from family pets.
Cute dogs but not great quality. Also lot's of scammers.
If you are looking for a good quality Chihuahua bitch to possibly breed form, look for the best example and healthiest girl you can find.