I found this thread while looking for some answers myself. 3 springs ago we bought 12 leghorns TSC. All were hens. Since then we have steadily lost 7 of them to lash egg. I didn't know what it was until early this spring, when I got the nerve to cut open the hen who had a large lump in her belly. Today I have another hen in chicken hospital that passed a small lash egg. After the last one died I treated the whole flock with tetracycline. No vets here. Thought I had nothing to lose. After all this time I was hopeful I had seen the last of it. I wonder, is it something to do with TSC chickens or will I eventually lose the remaining leghorns and my 7 sex link pullets too?
