Are they eating right? Give them Layer or All-flock and they will be fine - and some treats every couple days.
Are they sick? No - your chickens do not look sick - they look good to me.
Do they have everything they need? Food, water and you - so YES they have everything they need.
Are they cold? NO - it isn't -10C so they are NOT cold. You might feel cold but chickens are far more hardy than you or I.
Why do they fight so much? They are chickens - it is The Way of the Chicken. Let them be.
And other issues Don't trouble trouble, till trouble, troubles, trouble.... in other words relax, and enjoy their antics!
You are doing an awesome job as a chicken keeper - no need to worry or stress or fuss.

You need to worry about/take care of yourself, or there will be no one to give your chooks all the love and comfort and care you do!!!!!