If you have two hens and a roo, you will want a couple more hens.
The temperatures aren't too low for them, especially with completely covered huts. You might want to make sure that nothing is coming by to visit them in the mornings.
Do they have shelter from the wind? Do you provide hiding places where they can cuddle together?
If there are three of them, are they all the same gender? If not, that could very well be a problem since the ideal ratio is one male to five females.