OK, you scientific types who demand control groups, minimum of 30 subjects, double blind, placebo, this is not the thread for you!!!
Some of my simple dumb country boy observations:
By way of an abstract - Open feeding is beneficial for the beekeeper who finds himself/herself needing feed in a hurry, has several hives of similar field strength, not enough time to devote to tending to each one individually, and the hives are showing signs of distress from lack of forage. I used open feeding during a dearth - and a dearth that occurred during a draught - and a draught that occurred during extremely hot weather. I did not intend the aligning of these horrible planets, but that happened none the less.
1. open feeding rewards those hives that have sufficient foragers. Those that are weak when it comes to a field force may derive little or no benefit since they have to put on more of a hive defense to protect against the secondary effect of open feeding - robbing. Among hives that are evenly staffed with field bees, the open feeding is both effective and convenient.
2. open feeding benefits the enemies of the honeybee. Ants, yellowjackets, paper wasps, predatory wasps, bald faced hornets, and waspy looking wisps, and wispy looking wasps, as well as lanky stingy looking things I frankly had never seen ...or heard...before. One tiny blue wasp would chirp when other wasps got too close!! If you want to see a parade of nasty suckers, open feed and see who comes a callin....If you are determined to open feed, the bucket should be a sufficient distance from your hives so that you don't attract ants to the hives. I had a weak nuc made of old wood that had many holes. The ants were able to attack the nuc from so many holes the bees could not defend.
3. effectiveness of open feeding. The bees were able to suck down a large amount of 1-1 in a short amount of time. That's pretty effective in my opinion. The only other factor bearing on effectiveness is bee mortality. With open feeding, you will have bee mortality. Some bees will be found drowned in the feed. This is not clearly due directly to the open feeding, but may be a number of factors, such as a worker just reaching her natural end, being unable to lift off after a full honey stomach (again, age, wear on wings). Perhaps a mis step or being stepped on by another bee may cause a bee to become drenched, and while grooming it is stepped on again and then unable to lift off. It is unknowable how many similar deaths occur comparitively with natural feeding, say from spiders waiting on the bloom, birds because the bee had to fly farther. The workers may actually suffer less wear and tear if the open feed is placed within a hundred meters of the hive - I think the trips will be shorter, but the bees may make more of them until all available space is filled. I also wonder if the water carriers are enlisted to carry 1-1, and if this saves them from having to carry so much water, and beefs up the field foragers.
4. methods. I started with a 5 gallon bucket and sticks. Quite a bit of drowning. The sticks' irregular surface defeated the purpose, not allowing bees to have a foothold. I then used one inch square cedar stakes. This works well but you need several side by side, and going into the bucket from opposite sides, in an alternating patern. This turned out to be one of two acceptable methods. The next method I tried was a chicken waterer. Man I had high hopes! Sadly, the galvanized one I tried had a design flaw that attracted bees inside where more drowned than with any other method. I am curious about the plastic waterers, as their design is different and probably would do just fine. AT the same time, I tried a 5 gallon bucket with ...pine straw on top. This turned out to be my favorite feeding method. The pine straw doesn't so much float, but forms an interlocking mat. I am now trying the smaller chicken waterers that hold a quart. I may give a follow up later on this.