Half of my six hens have started looking like this in the last few weeks. These are my first ever chickens so I'm not sure what is going on. And my dominant hen now has a broken beak tip. I kinda feel like I'm failing at the chicken-mothering
Looks like frostbite to me. You may want to increase the ventilation in your coop while reducing any direct draft. High humidity, if not properly vented, can cause frostbite injuries even right at freezing temperature. If you have water in your coop, set it outside in the run.
What have your temps been? Are mosquitoes still active? It looks very much like pox, but if it's too cold for mosquitoes then...
I am not liking the looks of the beak in #1 and #3. Any lesions inside the mouth of that bird(s)?
It also looks like fowl pox to me. Dry pox on the skin is usually survived, but if you see yellow patches inside the beak, she could have wet or diphtheritic pox, which can be more deadly. Pox doesnot respond to antibiotics, but if there are any lesions on the eyelids, I would recommend some antibiotic ointment such as Terramycin, or a non-antibiotic eye gel such as Vetericyn. Pox scabs should be left alone to not spread the virus, but iodine can be applied to help dry up the scabs.