We took the winter wraps off the second week of April.
For this trip, Dad and I were adding Formic Acid pads as a mite treatment to both the hives. The formic pads come inside a clear plastic wrap. The clear plastic is cut away, leaving behind the foam pad which stays inside it's blue plastic cover. There are holes in the bottom of the plastic and the pad is set, holes side down, on a couple of sticks. The sticks keep the pads off the actual wood frames of the hive.
Because of the thickness of the pad and the addition of sticks, a rim spacer is needed to create a little space - so we added those to--that's the lime green coloured rim in the photo.
The Formic also penetrates the capped cells to kill the mites, and often it kills the pupae too. But not treating would make things much worse. We examined the sticky mite boards prior to putting the formic on and Hive #2 is heavily infested - and they have less bees.
We topped up their sugar water and then closed up the hive.
While taking photos I noticed some brown spots on the front of the hive. I don't think they were there prior to taking the wraps off. It could be Nosema (I hope not) or possibly a dysentery.