Consistent hatching issues with one line of Orpingtons

[Ivy_Chickens]

Okay, I recently a few good hatches after some incubation issues where I hatched out a number of different varieties of Orpingtons and Wyandottes. All good but one. I have 4 silver laced Orpingtons I got from a show breeder who quit showing and left his birds in tiny cages. They arrived looking like they had been through a tumble dryer with missing feathers and so forth. I expected an uphill climb. First, I got a month of infertile eggs from them. Then a lot of quitters. Finally, slowly they starting making it to lockdown. Que the theatrics. I don't typically intervene with hatching but they were consistently pipping on the small end or externally pipping and not making any progress. So I've managed to pull a handful through. Something I notice that happens a lot with them is that when I candle before lockdown, there's already a red smudge suggesting they're opening veins in the membrane. The eggs are noticeably larger than my other Orpington eggs, and the shell quality is usually worse. I am trying to fix it with nutrition and supplements, but it's a battle. What do you think? Genetics? Older birds? Neglect leading to low hatchability? Can I fix this?

 

[sourland]

Possibly older birds still recovering from neglect. Another possibility is excessive inbreeding. I used to hatch eggs from a highly inbred WCB Polish line. Hatchability was very low, but quality of birds was very high. Roosters also tended to become infertile.