I have 2beagles that were 1&2yrs old when we got them i leashed them at first when we got them and just constantly took them by the chickens i loved on and petted the chickens while they were there and they just figured they were family at the beginning of this summer while we were working outside my daughter put them in the run with the chickens and our bunny so they wouldn't take off to the woods and forgot they were out there she was so tired and they were out all night when we went to feed the chickens in the am there was both dogs in the nestboxes sleeping with chickens and the bunny laying on and around them any dog at any age any breed can be taught new tricks you just have to take the time to work with them and it is not going to happen instantly so don't worry and don't be impatient