You're speaking with Dr. Michael Salkin. Welcome to JustAnswer. I'm currently typing up my reply.
The two likely respiratory infections you're seeing are turkey coryza (Bordetella avium) or avian mycoplasmosis (infectious sinusitis of turkeys). The symptoms of one mimic the other. Antibiotics alleviate symptoms but can't cure the infection. Some recovered birds remain carriers. I would dose the affected chick and Orpington with tylosin (Tylan-50 in your local agricultural merchant store) at a dose of 40-60 mg/kg of body weight intramuscularly or you can give the same dose of the injectable solution directly into their beaks once daily for 5-7 days. Deaths aren't common.
Please respond with further questions or concerns if you wish.
It's much too late for that, Jessica, and I'm going to ask you not to treat the healthy one unless it breaks with similar symptoms. If you have room to quarantine both your hen and the ill chick, please do so. Please continue our conversation if you wish.
Thank you for the good update and your kind accept. I appreciate it.