I'm so surprised a Pug killed chickens. I lost one of my Pugs to old age last December so I'm down to two but only the youngest and most aggressive one ever showed any interest in them...after two short chases and being yelled at, she stopped paying attention to them too. That was over a year ago. My Chihuahua walks wide circles around them keeping a close eye over her shoulder to make sure they are not going to 'get her'.
I have a new rat-boston terrier mix who is four months old now. At first she was petrified of them, but got used to them. That lasted a week until she decided they are fun to play with. She is in training. The four dogs have access to a fenced part of the yard that they can't get out of, but the chickens fly over it and come in. The pup will go after one and if it turns on her, she turns and runs...most of the time they just squak and fly back over onto 'their' side. But she understands a loud NO which will cause her to stop chasing them immediately.
I take her...leashed...out to the coop with me. She is learning. It isn't killing one she wants to do, she wants to play with it.