The older GFF CL lines laid tons of huge blue eggs. The Rees ones (Gff only have Rees available now) Laid smaller, greener eggs, hens are late starting and were poorer layers. Maybe it is inbreeding.
If I were making sapphires I would try to source some of the original lines.
There would lines A and B. Not C or the Rees. The first import carried recessive white, so any white legbars are usually original import.
My friend has some of my original hens/ their off spring. She could probably send you eggs. Are you in California?