Has anyone any ideas/thoughts about pearling/semi pearling/non-pearling? I am not too sure that factor/s involved which effect the degree of pearling are well understood. It has been thought in the past that two doses of an autosomal recessive (m/m) would produce non-pearled birds, heterozygous M+/m would produce partially-pearled birds, & two doses of M+/M+ would produce fully pearled birds. However, in some places it is my understanding that only fully & semi pearled birds exist, ie, no completely non-pearled birds @ all. This would tend to indicate that another/other factor/s (that which removes, or helps to remove all pearling) doesn't exist in those places, otherwise, any birds pure m/m produced would be non-pearled.