thinking sinusitis, sound like the turkey has it. Yes give it to the turkey also. No would not give to the one not sick.
Get a small bottle, little goes a long way. Hope they dont have blackhead, need to take dropping to vet to be checked.
I lose very few peachicks from disease.
1. I dont mixs with chickens
2. raise on wire first 2 months.
3. feed a medicated starter first 3 months.
4. worm with safe guard(panacure) start at 2 to 3 months
They dont just drop dead, trouble is if sick they dont show or act sick until near the end.
Prevention so much better than treatment.
I raise poults the same way, lost none last two years(turkey)