It is sad my friend, but you have a problem, chickens are escape artist and really believe the grass is greener on the otherside !LOL
Unless you completely secure an area for them this will continue to happen they will not learn by another chickens behaviour.
Your choices literally are secure the birds or train the dogs.
Have a successful week ahead sorry for your loss. 😎
@katiebeth
!ALIVE
RE: And then there were 4....