Oncidium with Bright Yellow Leaves dying

[wiacomm]

Hello,
I have 4 oncidiums of various types, Sharry Baby among them. All of them have now gotten some bright yellow leaves, some are yellow stripe down the center. What in the world could cause this?
My den bigibbum also has the smaller bulbs whose leaves turned yellow and fell off. Now those small bulbs have no leaves and are barren. Larger bulb is starting at bottom turning yellow and will fall off.
I have just moved to a new home. So all new growing area in a south facing window with blinds and sheer curtains. But the first day here they got put into a south facing window with direct sunlight for about 4 hours before I found them and moved them. Could that be it? Every plant I own is pretty much dying in the new home. They DONT like moving. I do have a growing area for my houseplants (begonias, african violets, succelents etc) , I keep florescent lites on them and they are recovering ok. Should I put the den and oncs under the lights? I have some excellent sunlight here tho that is east west north and south that I would like to take advantage of if I can.
Any advise on the yellowing leaves would be much appreciated.
I have read on the forum and found some great advice on saving plants, I just hate to unpot these things one more time, if I need to tho I will.

ps, I have put the oncs and den in baggies to keep more moisture on them??
Should I move them to shade to see if they will recover?