No way should they be on medicated chick starter. At 5 months old, use layer feed. Chickens need roosts/perches. I recommend checking for mites and lice and treat them for worms. Offer treats like boiled eggs, tuna, shredded cheese....
If the chicks are hatching 2-3 days late and still with that much yolk unabsorbed, I would suspect your incubator temp has been running too low. I recommend using a digital thermometer and calibrate it before use. There are many...
I made and use homemade cookie tin heaters under my waterers. I bought 2 used cookie tins at Goodwill for $0.50 and wired and installed a light bulb socket in each one ~$2.50. Put the lid on and sit you waterer on top of the cookie...
I'm not convinced they are barred rocks. The one in back looks more gray than black. I believe the one in front may have had a barred parent. When you can, post pictures of the birds individually to include the legs and faces. Does the...
Is her foot swollen at all compared to the other one? Bumblefoot will present with a small black scab/dot on the foot pad. Wash her feet well and inspect again for signs of this. She may have sprained her leg/ankle and is guarding it.