i have a firstaid cabinet/chest in my quarantine room, its chok full of things i use on the animals, cant think of what is specifically for the chickens off the top of my head but heres a few things in there
flubenvet (dewormer)
ivomec cattle pour on (for parasites/worms)
denagard (antibiotic)
apple cidar vinegar
esb-3 (for coccidiose)
bandages + self sticking tape
scissors
guneapig nail clippers (for trimming chickens nails - normally only need it for the indoor chickens who dont have much hard ground to wear nails down on)
various size heat lamps
tweezers
wound spray
cotton buds
syringes without needles
eye wash
sanitary towels / chicken diapers
chicken saddles
multi vitamins without iron
vicks vaporub
then i have the homemade things...jars of dried crushed garlic/peppers/pumpkin seeds etc and a little bottle my pharmacist made for my chickens when they had a respitory infection, its all naural ingriedients that u put in an oil burner and it helps relieve the mucu to help yo breathe more easily
i dont need to use these things often but like to have them there just in case, we live out in the sticks so its not easy just to nip to the shop if a chickens ill...