Why would a hawk kill a chicken but not eat it?

[ackie]

Can you shoot a hawk if it is attacking chickens? In order to shoot a hawk, you will need to obtain a permit called the Federal Migratory Bird Depredation Permit. Hawks are protected in the United states under the federal Migratory Bird Treaty Act of 1918 (16 USC, 703-711). You can shoot or kill a hawk only if you have a special permit from Wildlife Services. Additionally, shooting is authorized only in specific situations that involve public health and safety. Along with a permit, there are rules that you will have to adhere to before attempting to shoot a hawk. As a nuisance (birds of prey) such as hawks are to poultry keepers, they can not be killed, trapped, or caged, even if they wipe out your flock, without a special permit.
https://www.fws.gov/forms/3-200-13.pdf

that's what I thought