When you say someone has chickened out of something, you mean they have failed to do something, or they haven't tried to do it, because they were afraid.
Johnny says he is an action man but he chickened out of riding a horse.
Are you absolutely sure you want to go bungee jumping with me? I don't want you to chicken out at the last minute.
If you say someone is no spring chicken you mean they are not young.
I don't go partying every night any more. I'm no spring chicken and I need to have a good night's sleep.
According to the Guinness World Records website, the oldest living chicken was found in Maryland, US, in 2011. It was called Muffy and was 22 years old when it was found.