Concerned...Shivering Chicken?

I'm a little bit worried about my Light Sussex, Mo. She's started shivering at the moment with the cold weather and doesn't appear to be herself today. They're not really eating too much like they used to, i have heard conflicting stories about heating and decided against it as apparently it can be worse for them. She has just started sneezing occasionally and i am just wondering if there's anything i can do. Her and the Silkie were born in about September time, along with Wonky the duckling, who i know they both miss. She's alot bigger naturally but appears to be suffering more. They didn't leave their house or run (they have free roam of the garden during the day) when we had all the snow the second time and I just hoped someone might have an idea. They spend the day out and about or huddled up outside my back door. I am tempted to bring them indoors, although that would generate mayhem! I'm just worried as she's not happy and appears to be walking funny, but i'm not sure how much of that is due to the cold.
Any ideas or suggestions are welcomed.
Many thanks
Kirstie

no she sounds fine, a small drop of 'snot' on her beak from her nares but otherwise all sounds fine, just the behaviour and the shivering that's concerning me :o(

She seems hesitant to put her foot down, i wasn't sure if it was to do with the cold initially. her legs are shaking, like shivering and she doesn't seem happy. She's just started walking with what looks like a limp now, so i'm not sure if perhaps it's a bit sore... i have looked at it and although red and cold she doesn't appear to flinch when touching it, although she doesn't like being handled at the moment, which she did until about a week ago! I can't have another leg problem after loosing Wonky because of his.... eek! :o(
 

Both legs are shivering, but it's one she seems hesitant to stand on and kind of limps now. I will see how she is tomorrow, fingers crossed she was just having a bad day and perhaps twinged it on something? It was the shivering that was the main concern and the lack of eating, but i will try your recommendation. I'm not sure what age they can start eating corn? but if that'll help i'm game to try it!

I've started giving them the porridge type thing with corn which she seems to eat, and extra straw too.  She's acting all dizzy now! A bit like she's been on the vino... I brought her indoors for a few mins and she appeared to be coughing although her breathing sounds clear. She has a massive crop too so I'm really not sure what's going on with her. I'm going to see what it's like tomorrow but I'm wondering if it's impacted and she's a bit dehydrated perhaps? She's got a limp too but clearly isn't right, so might well be a trip to the vets Monday :o( anyone ever come across such bizarre symptoms?

She's not eaten much recently but did today so am going to check in the morning before I give them their food to check. Failing that I think I will talk to the vet as I will probably have to see him anyway as my parrots poorly still! Not having a good run of it with my birds at the moment as lost 2 in the aviary too!! I will see how she is but have a feeling a vet trip might be worth it.