i'm not a pro too... but this is what i meant by my previous statement regarding inbreeding... info from wikipedia...

Results of Inbreeding

Inbreeding may result in a far higher phenotypic expression of deleterious recessive genes within a population than would normally be expected.[1] As a result, first-generation inbred individuals are more likely to show physical and health defects, including:

a. reduced fertility both in litter size and sperm viability
b. increased genetic disorders
c. fluctuating facial asymmetry
d. lower birth rate
e. higher infant mortality
f. slower growth rate
g. smaller adult size
h. loss of immune system function.