If you have more than twelve beehives in your apiary, then you probably feed some form of antibiotics or take some precautions against mites. Lately I have been helping a beekeeper near Niagara Falls Ontario Canada as he works to unwrap his beehives from winter hibernation. They are covered in black garbage bags.
I watch as this veteran apiarist feeds each hive small amounts of medicine in three successive visits - three doses each spring. He keeps Oxysol 62.5 mixed with white cane sugar about 20:1 in a vacuum sealed glass container in the truck, and we sprinkle one tablespoon full on the top bars of every beehive we inspect and find alive in the month of April. This will protect the hive from American Foulbrood and European Foulbrood, otherwise known as Chalk Brood. These are bacterial infections - both are diseases that decompose or otherwise transform the Queen's eggs into smelly brown gravy.
I am researching an article on natural ways to protect beehives from disease and I could use all of your knowledge... how do you winter your bees? What medicines do you feed them? to keep them healthy and help them resist American Foulbrood?
The only way to prevent american foulbrood. keep your hives strong. Weak hives bring on bee diseased. The only medication I use in my hives is Fumagilin-B. everybody has some kind of Nosema in their hives. I wont use medication to treat mites. Medication for mite treatment help bring on bee diseased by weakling a hive. chalk brood is a fungus. it is caused by a moisture problem in a hive.
I use drone comb to kill mites in my hives. put the drone comb in number 3 position. leave it there for 25 days. Take it out and put in another new frame. freeze the first one in the freezer till its time to use it again. you need two frames for each hive. the bees will clean up the comb with the dead drone larva and mites in it. I do this treatment 4 times during the bee season.