She is notoriously known for her prey-drive and has killed chickens in the past according to my roommate. As of late, she has been harassing the chickens almost non-stop. She barks at them under the fence while making holes trying to get in, she isn't learning the same way we're trying to get her stop fence fighting with literally every dog that lives next door. We get her to come in, close the door so she can calm down for a bit and try again but immediately starts with the chickens again. We've been doing a shock collar on her, although mostly vibrate and noise since her owner doesn't like shocking her but will if she's not listening to the other two "warnings." None of these are getting through her head she needs to leave them alone in the long-run. She knows when it goes off it means to leave it but the second it stops and/or she doesn't currently have it on, she's right back to harassing them.