Dog killing animals

Question
QUESTION: My Mom has had her dog, Jesse, for 10 years.  A neighbors cockatoo flew into the fenced in yard, and he killed it so fast, then just dropped it and forgot it.  The next day, he did the same thing to a turtle dove.  Within 2 weeks, it was a cat that got into the yard.  He had never done this before.  Is it something now we should worry about?  After the cat, he went into some kind of shock.  She couldn't even get him to respond.  The vet told her "He is just getting over his 'kitty-kill'  After 2 days he was back to normal.  Also, should she be worried about the neighbor children?

ANSWER: This is normal behavior,as dogs are natural predators,and some breeds have stronger instincts then others

Human and animal aggression are two different things,so you don't have to worry about kids,as many dogs hate animals but love people,my own dog killed a few birds as well,but has never shown aggression towards me

If you want,you can get back to me and let me know what breed he is,and I'll let you know if it is common for that type of dog

---------- FOLLOW-UP ----------

QUESTION: He is part yellow lab and part golden retriever.  Also, I failed to mention she had a cat living there for the 10 years he has been there.  The cat died last year.  Do youknow what the 2 day stupor was about?  Was the vet correct with his 'kitty kill' comment?

Answer
Retrievers are generally good with other animals,not really sure what the vet meant either-I have never heard of a 'kitty kill' either,so it might help to call the vet and ask him/her what she/he meant

But this in fact could be a hormonal problem,such as hypothyroidism,which can make dogs act weird,so it won't hurt to test him for that-this is rather unusual after 10 years of living with a cat