chick panic

Washing up and watching through the window hens pottering around the garden suddenly noticed them 'lift skirts' and charge frantically back to end of garden where the coop with mother hen Minnie and her one precious chick are housed. I rushed out to see what was up and could hear panic from inside coop. I opened up the roof and Minnie was flapping around scratching at floor and hidden chick cheeping as loud as I've heard it. It seemed to be trapped under her, caught with a long feather stuck well under its wing (it looked like it was impaled on it) I managed to free the chick before Minnie's thrashing and panic crushed it and they gradually calmed down. If I had not been there would it have resolved itself ? has anyone else come across something like this?