I would definitely keep the chickens away from the compost pile. Many people let chickens dig around them, and botulism can be a problem if chickens eat vegetation or part of an animal carcass that has been underground, under water without oxygen in an anaerobic environment.
Your hen may have not had botulism at all, unless she seemed paralyzed. Symptoms include paralysis that starts in the feet rapidly progressing up the spinal nerves to the wings, neck, and eyes, causing death from paralysis of the breathing muscles. But it might be good to keep the others from eating that. So sorry for your loss.
Your hen may have not had botulism at all, unless she seemed paralyzed. Symptoms include paralysis that starts in the feet rapidly progressing up the spinal nerves to the wings, neck, and eyes, causing death from paralysis of the breathing muscles. But it might be good to keep the others from eating that. So sorry for your loss.