I'm raising a batch of Cornish X. Started with 50 and am at 7 weeks with only 27 and more potentially goon to die. They get a starter/grower feed with 18% protein and 3% fat. I've cut back their rations thinking they were eating too much, but with no improvement. The hatchery says they are 'growing too fast' but at 7 weeks they are 1-2 pounds smaller than the growth chart says they should be. Necropsy reveals heart failure. I need to know what I'm doing wrong. What can I do to keep my remaining flock healthy until butcher (the hatchery said feed them all they can eat for the next week but I'm afraid they will ALL die at that point). And if I'm doing everything 'right' should I ask the hatchery for a refund? They tried to make it sound like some loss is just to be expected, but 50% seems unreasonable to me. Is there anyone who can help me figure this out?