How does this breed cope in a suburban yard?
I have three Aussies and we live in suburbia. We run between 10-12k's a day and a good part of that is through light bushland where they can be off leash. They spend most of the day lazying around but once the children get home from school they are up for a good play around, ball, frisbee, soccer....
How do they cope with livestock - i.e. horses?
Mine are all curious when they spot a horse or cow but won't chase them.
Are they good off leash (yes with training)
All the Aussies I know are great off leash and are easily recalled. With the correct training they are an excellent obedience and agility prospect. They are also great with flyball and other such sports.
Are they good with small animals like smaller dogs, cats and chickens?
This depends on how they are raised, our three have been around cats from the beginning and accept them as part of the pack. They are brilliant around other dogs, however if the male is a little bit rough with smaller dogs. As for chickens, I would never trust mine with them, they get very excited when they see a bird and will chase.
What are they like with other dogs?
My female adores all other dogs, male/female, small/large, puppies/adult. My male is fine with all females and puppies male and female, however other male dogs he occasionally will have issues with. As ridiculous as this sounds, my female will get especially excited when she spots another Aussie or BC.