hardy grass seed

I suspect you may be struggling, as grass depends on sufficient temperature to germinate.

However, I'm going to move your post over to General Gardening, as I think more regular gardeners will see it there.

You might be OK with a rye grass mix and some fleece Helenaj

http://www.telegraph.co.uk/gardening/problem-solving/why-winter-is-a-brilliant-time-to-sow-grass-seed/

If you get the kids play area types, they usually contain the highest proportion of rye grass ... although the destructive power of beaks and claws can put most children to shame 

Thanks New Shoot. I saw this article when I was searching for seed and it indicates that the temperature needs to be above 3C for the seed to even survive. I think that I may be struggling to reach those temperatures consistently over the winter - my chooks and ducks are half way up a mountain and the temperatures at this time of year can struggle. I'll give it another month and have a look again.