[shester77]

I just brought home a four month old red heller and she right away started chasing are baby chickens. Is there anything I can do to get her not to?

[shazamataz]

A fence.

Seriously, a Heeler is a herding dog, bred to work on farms, it's a bit unrealistic to expect one (a puppy at that ) not the chase/kill chickens.

You might be able to desensitize the dog to the chickens but it will take a lot of hard work. I would start in a similar way you would teaching a dog to leave food that has been dropped.
Hold the baby chick in your hands and if the dog goes to touch it just use the command 'leave it' and make the dog sit or push it away.
Work up to putting the chick on the ground whilst telling the dog to 'leave it'.

Finally you can try letting the dog off with loose chicks running around (once you are confident you have trained the 'leave it' command).