Please don't trouble yourself with guilt and regret. Hound people in general have had to witness many incidents in which their hounds were just "following instinct". It's sad and a bit disappointing (and to me, GROSS), but hey, it's nature! Giselle has killed many baby birds, but it's her nature and nobody can help it. Sorry you had to witness it I'm just glad you saved it and brought it to a wildlife rehab center. Good for you