I am so sorry to hear this...we have been through this horrible experience ourselves. About a month ago, we had 15 beloved chickens and in one night (first time we ever lost a chicken to a predator of any kind) a weasel killed 11 of them! The weasel ate only 2 of the heads off and just killed...
This is our Buff Brahma cockerel Papi (taken when he was about 3 months old).
What a difference a month can make! Here is Papi about one month later at just over 4 months!