We had the same thing happen two weeks ago. I had just driven two hours to get my twenty chicks from a breeder. We have two Kerry Blue Terriers, one is 8 the other is 12. They watched the chicks with interest, but showed no signs of wanting to do anything other than watch them. Well the day after they arrived, we were out working in the yard, and all of a sudden I noticed I didn't see them. The terriers can open the doors if they have a lever handle, and the 8 yr old girl opened the front door, went into the sunroom, jumped off the sofa -because the brooder box is three feet high...and killed all but one. The one remaining was hiding under the Ecoglow..needless to say we named it Phoenix! I was heartbroken! She didn't eat them...or tear at them. There was no blood. I think she thought they were interactive playtoys brought home just for her. So, that night, we built a top, and put the dogs training collar on her. She had to wear the "collar of shame" for over a week. She won't even Look at the brooder now. I had to drive back down to the breeder for more babies. Live and learn, but it sure can be painful!