I wonder if anyone out there can help throw some light on my border terrier x patterdale puppies weird behaviour when being fed.  She is about 10 months old and only exhibits this behaviour when being fed.  She starts to chase her tail, snapping and growling and bites at her legs as soon as she thinks she is going to be fed.  She will sit and wait for her food and when you tell her she can have it she eats for a few seconds then chases her tail and growls.  She does this even when given food in the shed she sleeps in outside and no-one is there...I can hear her from the house.  Other than this she is a normal. well adjusted, social dog.  Any ideas on the reasons behind this...and should I be concerned?  It seems very strange.  Thanks for any help.

If it's only at mealtimes that she does this then the only thing I can think of is that she gets very exited about her dinner and it has become a habit or a mealtime ritual.
Sally