Dying Bees in Observation Hive

I have a top bar observation hive in my yard which has been doing very well this spring. The hive contains a new package (hived in mid April) with an Italian queen and up until yesterday everything was looking good in there. The new bees were emerging from their cells and the bees were bringing in lots of nectar and pollen. They were working on the cherry trees in the yard. Yesterday my son noticed that there were dead and dying bees on the floor of the hive and on the ground in front of the hive. The bees that were dying were curled up a bit and looked sort of dazed and in some cases paralyzed. Does this sound like it might be the result of poisoning from herbicides/pesticides? The dandelions have started blooming here and quite a few of my neighbors have had the Chemlawn guy out to spray in the last few days.

I am wondering whether it would help to start feeding my bees again so that fewer of them will come in contact with whatever it is that is killing them. Or maybe there is really nothing I can do but watch.

I find this sort of sad and wish there was a better way of knowing exactly what is going on.

How many dead bees? A couple/few may be normal, but a good kill will have a carpet of death outside the entrance. Usually the chemlawn staff if herbicides which don't kill bees (at least not directly), but who knows what else they may be getting into.

There were dead bees all over the ground and landing board this morning. The living bees seem to have done a good job of cleaning out the dead bees over the course of the day and my hope is that everything will be back to normal tomorrow. There are a lot of new bees emerging from the comb right now so that should help boost the number of bees in the hive. The nights are still cold here so I was very worried when I saw so many dead bees - it wouldn't be good if there weren't enough bees to cover the brood nest at night.

After inspecting my other hives which are out at a friends farm I found that they also have dead bees on the ground. One of the hives had poop on the inner cover which makes me think that this is actually Nosema. Many of the bees are dying with their tongues sticking out. I think this die off is related to me having stopped feeding the bees and I am considering putting the feeders back on. Any thoughts on this from experienced beekeepers who run their hives without antibiotics?

The only way to diagnose Nosema is with a microscope. Bees poop. When confined like in a package they poop more. The field diagnosis for Nosema is to field strip a bee (pull them apart and look for an opaque white gut instead of a normal yellow transparent gut), but that's not 100%. Feeding anything will clear up Nosema. Feeding honey will clear it up faster.

http://www.bushfarms.com/beesnosema.htm

I wouldn't say that's what it is. It could be a lot of things. Are they starving? Is someone spraying pesticides?