We had to use a shock collar on our Aussie. It was our last resort. He'd work himself into a froth over the birds and killed a roo. We long tethered him to a tree by where the birds free ranged. Every time he'd get worked up, he'd get the "listen" beep. I personally think desensitizing him to their presence is working better than the zap. But I still don't and won't trust him alone.
Colby
Colby