Any farm girls on here?

So I have a predicament. I've never had this happen but my four cats all attacked one of my chickens that was out free ranging. I let them roam throughout the day and lock them up at night (the chickens) and my cats come and go as they please in and out of the house. They have shots, they are not declawed, but now they've killed (and started to eat my chicken, who btw was a huge hen). I feed them pretty steadily through out the day. My husband is saying that any animals that taste another animals blood need to be put down. They have never done this before and my flock is officially locked up.

Anyone experienced this? Did you have to put down your cat? In this case all four of them were gathered around eating the chicken....so I guess we'd have to put all four of them down?!

Update: So my husband is wanting me to figure out what I want to do since they are my animals. So I've made the decision to give my cats new home (minus one who will stay inside officially) and keep my chickens free roaming. They get so big and happy when they free roam and I'd hate to take that away because they also lay a lot of eggs. Our yard is covered in trees so I've never had a hawk problem and they get a lot of bugs out in the field. My cats are usually great but we've had a lot of friends ask for them so well just keep our oldest inside and give the other three away to good homes. You ladies are awesome! Thank you for your advice!