I'm so sorry for you and your sweet baby pigeon
I assume she needs the warmth and therefore went so close near the heater. So being close to the heater is good, another option would be a red light (heating) lamp to keep her warm (always with enough space around so she can shuffle to a cooler spot if she wants to).
I don't have very much experience and most of my experiences are based on a wild pigeon species called common wood pigeon.
We have a close friendship with such a pair of wild pigeons since many years and when they are old enough they bring their babys to meet us. One year one of the babies developed an illness: breathing problems, fluid coming out of its beek, tiredness, trying to eat but somehow not beeing capable to do so in a sufficient way. We tried to offer softened food, placed extra water, but the baby being a wild bird we couldn't get that close and first couldn't do more. Some days later the baby sat in front of my parent's terrasse door and looked inside our living room. It clearly asked for help. This day I managed to catch it - so weak it had become. We brought it to the veterinarian clinic. Sadly we were too late - the baby had lost so much weight and the issues were so severe so the vet recommended euthanasia for the little one. Because of its bad condition they didn't do special tests, but there are special tests for such cases. As biophiliac mentioned above the vet mentioned Salmonella as possible cause.
Another possibility could be Trichomoniasis, and I think this was what 'my' wild baby suffered from.
Try to look carefully in/down the beak of your baby and watch out for yellowish or greyish stuff, it would be a typical sign for Trichomoniasis. Other signs: struggeling for breath, difficulties swallowing, puffed up feathers, loosing weight to starving; sneezing and 'coughing', throwing up. Some individuals can smell fishy out of their beak.
For diagnosis vet has to make a swab and put it under microscope. In my country (Germany) Trichomoniasis is treated with Spartrix, Metronidazol or Ronidazol - I don't know about the US. Yellowish and greyish stuff has to be VERY carefully removed with a Q-tip out of the beak and throat. Water dishes have to be washed daily and carefully and then dried out completely for 24, better 48 hours before new use.
Another possibility could be air sac mites. Did your baby loose her voice? Does she sneeze, retch and throw her head around? Does she breath with opened beak? Do you hear little 'cracking' sounds while she is breathing? Do the symptoms get worse in the evening and at night? Treatment would be Ivermectin (spot-on) from vet.
There are even more possibilities such as lung worms.
Because there are so many possibilities I would recommend a vet if possible. With the appropriate tests cause and needed medication could be defined.
I hope with all my heart your little one will pull through
She is such a fighter and you are caring so well for her! Fingers crossed and best wishes
She flaps her wings all the time too. One of her feet had curled toes, so I taped them straight and that seems to be helping a lot.
I’ve heard of people safety pinning wing feathers together, but I’m afraid that could have negative affects on her.
She went over by my heater and sat there as if it was cold, but it’s 72°F in here.
