How to write a letter to your neighbour for the Inconvenience caused by your Pet

Apology letter:

 Dear sir,

I heard from my son that today morning our cat ate up one of your chickens. This is in fact unfortunate and I apologies sincerely for the life caused. Our cat is usually well behaved and I cannot imagine what got into her. This morning, Moti has been properly punished and I am sure it will not bother your chickens  again. I have asked my children to keep an eye on Moti and see to it does not cause you again your any inconvenience or damage in future.

I am sorry for what has happened.

Yours friendly,
(your name