I had a very similar experience breeding the lurcher in my picture, I bred her with another handy lurcher (no relation) and every thing was going fine in the pregnancy and when she gave birth to 11 pups they seemed healthy until there eyes started to open and I saw they were cloudy blue it was my first time breeding lurcher's I had only bred terriers in the past, so at the start I put it down to that until they started to get on there feet they were wobbling couldn't walk strait couldn't stand then they started to vomit and have seizures I went to the vet about it with no conclusion. it was si