Hen has become weak and not standing up - possibly dying? Old age? Help!

[flipflops]

I only have 2 hens remaining from my flock that I had of 6. They are best buddies. They are 8 years old this month! The one who is acting sick and possibly dying is a blue maran. It started last week when we had some severe cold weather. Like down in single digits for about 2 weeks off and on. She started just barely walking around, low energy. I put a little flat panel coop heater in there. She has been eating her normal layer crumbles, scratch, water, and some eggs also! I noticed sometimes when she would chase the other in the run she was tripping and falling. she has a large spur that has grown out also, surely it is not this causing the issues? They have not laid eggs in over a year now. They have just been my pet. Today i saw my australorp outside but not her. Went to find her laying in her coop. I picked her up and she will stand for a minute then falls back over and closes her eyes. Is she dying? This could not happen at a worse time as we are going out of town for a week in 2 days. If she passes my other one will be all alone for a week until I can find some other chickens or pullets for her. Any help is greatly appreciated.

(Attached is a picture from a few days ago of the spur, and her today as I found her)

 

[Wyorp Rock]

I only have 2 hens remaining from my flock that I had of 6. They are best buddies. They are 8 years old this month! The one who is acting sick and possibly dying is a blue maran. It started last week when we had some severe cold weather. Like down in single digits for about 2 weeks off and on. She started just barely walking around, low energy. I put a little flat panel coop heater in there. She has been eating her normal layer crumbles, scratch, water, and some eggs also! I noticed sometimes when she would chase the other in the run she was tripping and falling. she has a large spur that has grown out also, surely it is not this causing the issues? They have not laid eggs in over a year now. They have just been my pet. Today i saw my australorp outside but not her. Went to find her laying in her coop. I picked her up and she will stand for a minute then falls back over and closes her eyes. Is she dying? This could not happen at a worse time as we are going out of town for a week in 2 days. If she passes my other one will be all alone for a week until I can find some other chickens or pullets for her. Any help is greatly appreciated.

(Attached is a picture from a few days ago of the spur, and her today as I found her)

I'm sorry about your hen.

The spur may be tripping her up, so you can try trimming it to see if that makes a difference.
If she's tripping a lot, she may not be getting to food/water and staying hydrated and fed, but it sounds like you check on her often to see that she's getting what she needs.

However, she may have more going from what I can see of her comb, it has a slight purple tint to it. This can indicate decline and also reduced oxygen.
I know this is difficult to read, but she may be actively dying, but it may also be she's just unwell, weak and in need of intervention.

I'd work on getting electrolytes or sugar water into her. Sugar water is 1teaspoon sugar to 1 cup water. I would give it to her slightly warmed. Electrolytes that you purchase are fine to give.
See if she perks up with hydration.