I decided to share my experience treating coccidiosis with cayenne pepper, there are commercially made products that are more effective, however they are not always available in time to save the chicken. My birds are raised on the grass from day one so around 8 weeks old they sometimes get coccidiosis. I have tried using garlic and the milk flush in the past but they didn't work for me so I use cayenne pepper. All my chickens/turkeys treated with cayenne have recovered.
Cayenne contains lots of vitamins (A and C as well as vitamin B complex) and minerals (such as zinc, iron, copper, potassium, magnesium, manganese and selenium). I know in humans it is very good for the heart and circulation. It is also good for increasing the appetite which is good as poultry with coccidiosis generally don't want to eat much.
I use cayenne powder but flakes should work the same, mixing it in with the food is the best but I also add a little bit to their water as well, about 1/2 teaspoon per gallon of water. To add it to their food it is easier if they are still eating starter because it mixes in easily. To feed with crumble or pellets they get more when it is mixed with a tiny bit of water first as it sticks to the pellets better.
For chicks under 8 weeks probably a teaspoon or two would be enough once a day until they are better.
8 to 12 week old chicks need about a tablespoon.
Over 12 weeks they would probably need 1 1/2 - 2 tablespoons.
Sometimes it is necessary to force feed them if they refuse to eat on their own. The easiest way for me is to mix the cayenne powder with a tiny bit of water and roll it into pea sized balls, then pop them one at a time into their throat, making sure they swallow them. This way helps because you know that they got enough. Just remember not to touch your face after feeding them cayenne unless you wore gloves or washed your hands REALLY well
This is what worked for me, just sharing in case anyone needs it and can't/doesn't want to use conventional medicine for their birds.