Line breeding is great if you go father to daughter or mother to son. However, a lot of folk are breeding sister to brother (ie. breeding adults from the same hatch) and this tends to bring out a lot of the recessive traits and defects. Know the breeder, ask lots and lots of questions especially about the brood stock. There are a lot of scam artists out there just looking to make a quick buck off of you, so you have to be careful.