I have talked to a good number of breeders this year, and one thing is clear...this was a very difficult year for queen rearing. Why? Hard to say. Why did many states see 50-80% overall hive losses last winter. Hard to tell.
But one thing is true for me. I've done everything the same as in years past. And this year, if I got 50% takes on my grafts, I was happy.
Some things you should keep in mind:
Grafting before the summer solstice is different than grafting afterwards. Bees are much in tune with the shortening of the day light, and even the slowing of the flow. And I have found that feeding alone has limited results without a flow stimulating the bees to bring in nectar.
I shut down grafting a few weeks back as my last two grafts was 5 and 4 out of two grafts of 32. Nothing to write home about. Earlier in the year, I had some good grafts, 30 out of 32 and some real lousy. For the most part, if I was getting 50% take, I was happy.
Don't let anyone fool you. Every breeder has difficulties from time to time. Those who never say they have anything less than something like 98% every year are mostly full of crap.
I keep very detailed notes. Temp, what was used to prime the cups, strength of hive, etc. And sometimes no matter what you do, it just seems like the bees are in no mood to make the cells you want.
Keep chugging along. Although at this point of the year, your not going to get much. April, May, and June....great grafting time. July and August....I just waste my time.