Think it was created in the 80's and was definitely a cartoon animation (along the style line of Watership down). The opening scene I think was of a Farm gate during a snowy winter, and a fox lived on the warm. There was a chicken house, and some wonderful animation.

Not Fantastic Mr Fox.

Any suggestions would be really great. Cheers.

I don't know about the fox being english, but could it be "The fox and the hound"?

There's the series "The Animals of Farthing Wood".
IMDb synopsis:
A herd of animals must immigrate towards a paradise called White Deer Park while making new friends and avoiding dangerous obstacles along the way. The second season continues with The animals facing a rivalry of blue foxes to stay in the park while fighting winter and losing family members. The final season indicates a battle against a bullying herd of rats who want the park for themselves after the great white stag has died; the park needs not only a new leader but also a miracle to fight against the final bullies of rats to the end.
The Animals of Farthing Wood (TV Series 1993

Here's Part 1 of Episode 1:
the animals of farthing wood season 1 episode 1 part 1 - YouTube

I just found the dates on it: 1993-95. So, that's far too late for you. Also, the opening scene isn't in the winter. So, this likely is a miss. I'll keep thinking of other possibilities.