Weasels are little killers that seem to kill for the joy of it. I have built holding cages, around the funnel, inside the main body of the recall pen (Johnny house, style. Works for other style recall pens, too). If anything other than a quail enters through the funnel it will be confined in the holding pen. Doesn’t prevent the lose of birds that have returned to the pen, but, saves the majority of birds that were not released for training. I have had a weasel, after the killing spree, take a nap while still in the pen. Another was under the pen. If they are still around, well, that’s a good thing. Bittersweet revenge for me and deadly for it. Smart little critters that may return, if, not eliminated. Good luck.