Thanks all - I'll pass your comments on to Rex. It was funny after the fact because as we were all walking back up to the house Rex turned and took one final run toward the back of the property, barked, and them came running back. My husband translated it "Yeah, and stay out".
He has been a great guard dog for the chicks. He was not raised with them. In fact he was 4 years old when I got them this spring. I was so conerned for nothing because all I had to do was show them to him, hold one till Rex calmed down, pet it and tell Rex how much I loved it. I had to tell Rex "guard the baby chick". Of course that first day he was excited and would try to climb in the box with them, barked at them, even looked like he would grab one but I kept it up for about 10 minutes and then he laid down next to the box of babies and there he stayed. One night I literally tried to drag him out of my bathroom because he had slept inside with them for a week and he growled at me. That's when I knew he took his job seriously and I no longer had to worry about him eating the chicks. They were his.