q1 - semi-automatic handcuff mechanism

[desbromilow]

so I have a few questions playing on my mind, and given the brain power and experience of this team, I thought I'd ask.
first question - I'm in need of a mechanism which could best described as a handcuff on a stick.
the mechanism would need to be able to snap around the leg of a pig and hold tight. The leg dimension varies from pig to pig. ideally it would need to be able to snap around quickly (perhaps spring actuated) and hold until released.
The release needs to be a link-able mechanism which isn't slow or tedious to release. (thinking a button which lifts the ratchet pawl out of engagement)
the "arming" of the capture portion can be manually reset prior to use, but the release will be difficult to arm once in use.

Intended use - several pigs in a pen or race with weld mesh sides. The device would be poked through the weldmesh to grab a pig rear leg and pull it towards the fence so a lifting lanyard can be attached. Once the lanyard is attached, the device needs to be disengaged so it is not pulled through the weldmesh when the pig is lifted be the crane. For safety reasons getting into the pen with live pigs is not desirable.

Does anyone know of a tool or mechanism which can provide the desired characteristics? If such a tool already exists, that would be even better, but searches are coming up dry.

Thanks,
Des