My birds regularly lounge around quite a bit during certain times of the day.
More information would be needed to ascertain whether your hen has problem or not.
Something is likely not right. Her comb is wildtype rather than rose which is not typical of American Dominiques but not unheard of. Color proper. Her feathers look like she has not gone through the annual molt yet which is late. Comb is floppy. A picture of it up close needed, especially after she exerts herself a little. I am looking for a color change. Collect some of her feces immediately after she poops and photograph it as well. Verify tonight she is able to reach roost. I would isolate her from others and get her into a pen that is off the ground. Then introduce more protein to her diet.
If comb and feces like I suspect then you have a specific parasite issue at play.