What do you guys think?

I don't believe it is spread because of them eating out of the same pile of corn/feed. To my knowledge it is just easier if they're close to one another because the midge fly doesn't have to travel too far to get to the next deer. So yes it is something to worry about but not for the exact reason you're saying.

Hi, Im new as well.
I also have a question; I have a doe not growing as fast as the others. She is three weeks old; the appetite has become poor and her backbone is apparent.
she is sort of wobbly on the hindlegs, I think from not eating.
These are all rehab fawns (mule deer) and are being bottle fed (I'd like to get them to drink from a bucket as soon as possible, but right now they are getting the bottles). Everyone else, including an antelope doe, is fine but this doe has shown sort of an oily fur along her backbone in the last few days.
Does anyone know what this could be? Is it selenium deficiency? I can't find any matches on the internet for oily fur /deer disease.
She is drinking a lot of electrolytes; her feces are greenish from it. I have one bowl with that available, then several big bowls and a five gallon bucket of water.
One other fawn has some diarrhea (blackish-brown) and I treated with Sulmet (that fawn is 17 pounds, I went by the instructions on the gallon jug) pumpkin pie filling and 2 cc's of kaopectate for two days in a row.
I gave this fawn kaopectate (2 cc's) because she showed some looseness in the stool, but it is not bad like the 17 lb doe. This one is 13.2 lbs. She has gained 3 pounds since I got her (first day she was 10.1) and I've had her a couple of weeks. But all the other fawns have filled out in the backbone, and you can see and feel the vertebrae on her. She weighs the least of all of them. Two are bucks, three does, plus the doe antelope at 22 lbs.
If anyone has ideas on what this might be, please let me know.
Also, do I need to add Selenium and vitamin e to the feed?
I am feeding them Pet. Ag. Multi-lac and Nanny-lac; and adding probiotics a bit to it (the powdered stuff they sell at the ag store for baby ruminants).
they have alfalfa and timothy hay available at all times; calf manna mixed with deer pellets and some sweet feed , which has molasses in it, and oats and crushed corn.
I put powdered milk a little on top. They lip the stuff, I haven't seen them really eat it but I thought they should have it available Would the deer pellets and/or powdered milk have adequate selenium and vit E?
Thank you in advance for any help! You guys are the best,
Metis2007