I don't have a top entrance, but I do have a screened bottom board, and in winter it's stuffed underneath with polyester floss pad to prevent drafts, but it still allows some minimal ventilation. I didn't have a broodless period this summer,. and my biggest hive apparently sent off a big swarm so I have postponed treating for mites until after I harvest a little fall honey.
On the source of bees @amandabee
, when I buy a queen I buy from beeweavers, they are probably less than 100 miles south of me, and they have bred for varroa resistance, hygenic behavior, bees may be a tad bit hotter than a California Italian queen would produce, but I've had good luck with them, and the current Beeweaver hive is on its 3rd generation I think, I bought the mother queen in August 2019. Beeweaver queens tend toward a relatively small winter cluster, which reduces food needs, and build up pretty quickly in spring.
My other hive came in as a large swarm in spring 2017 I think, entered a deep nuc box swarm trap and when I went to put a feed jar on, I gently set the lid back down and got 2nd nuc box with frames on top to give them adequate space, they were quite gentle as a swarm. They produced enough to feed themselves in their first year, and were in a 10 frame deep and medium halfway thru summer, they sent off a swarm on mother's day 2018, I didn't catch it, but they built back up and usually have a very nice honey harvest despite needing 2 deeps and a medium to accommodate their population. This year they sent off a swarm and at harvest time (mid July) there was more brood than honey so I gave them a feed jar and let them carry on.
I will do a fall harvest when there has been a frost and I'm pretty sure they have put up what they can, and I will not take more than they can spare. Then I will treat for mites.
As far as buying bees or nucs, I bought 2 nucs in 2012. I buy queens and did my last removal from a house in May 2019
That was my neighbor, can't imagine how bees found his house - the ones in his house had been robbing my hives for 2 years - I did removal for free. I was more than paid in honey harvest after they were gone. that queen was replaced by a Beeweaver queen