These are the natural products I use on my standard sized breed chicken flock...
Hawthorn orally is great for those older birds to help keep blood pressure lower and keep the heart strong. (I have an 8 yr old hen with a heart condition. I mix 300mg Hawthorn powder in 2ml of Gerber Baby Food, load it in a syringe, (no needle) and down the throat it goes, under the tongue daily.)
Ginger, Cayenne, Cinnamon and Lemon Juice combined orally is a fabulous internal fungal/yeast killer. All of these ingredients increase circulation and exhibit anti fungal and anti bacterial properties. (1/16th teaspoon of each herb, 1 teaspoon Lemon Juice, it is used for internal yeasts and doughy crops. It is mixed together and given orally, under the tongue, .3 mg at a time until the dose has been administered, 3 times a day until bird is healed.)
Probiotics are a must to keep the immune system in tip top shape. Several times a week via food or water.
Aspirin for pain or arthritis. (Same as above, old hen has arthritis. She gets 1 baby aspirin every other day in a blueberry or a raspberry.)
ACV is wonderful to help increase appetite along with treating Gout, internal yeast prevention as well as all its other benefits. (1 tablespoon ACV per gallon of water, used a few times a month to help keep the gut sour, also used on any bird with a doughy crop).
Children's vitamin Poly Vi Sol (without the iron) is used on any bird that is sick, molting or just needs a boost. (1/4 - 1/2 ml orally under the tongue as needed.)