Thank you everyone. Your comments do make me feel better. I think I was in shock yesterday and now I am starting to accept what happened. I'm not happy about it but I accept that it happened.

Since my dogs are normally begging to get on the couch rather than wanting to go outside to see what they can hunt I'm sure my image of them as killers will fade. We took a walk today, saw several deer along the way, and they did not have any abnormal reaction. If they actually saw the deer they wanted to chase but were easily held back and distracted. The truth is they would be pathetic in the wild fending for themselves and an adult deer would probably hurt them. So, what I will certainly be doing for the future is never ever leave that gate open.

I did see the sibling baby deer and he/she seems to be living the same routine, munching on the same lawns, just alone. RIP baby deer.