I don't lock the coop* since i don't see the point when the run is already locked and secured with 1/2 in hardware cloth.
Of course, it will depend on your area. I live in the city so just dogs and cats to worry about.
My own dog will run after and sniff the chickens the first few times but she's ok with them now.
*(for ventilation in Arizona heat and easy for the chickens to go in and out on their own)
Edited by BruceAZ - 5/20/16 at 9:54am