Bug checks are pretty easy to perform, but I am not quite understanding why you are doing it. Their color is wrong?
Anyways- lice are easy to look for. Lift the feathers up and look at the skin focusing on the area around their vents. Any bugs seen? They are large enough to spot pretty well. If no, then look at the bases of the feathers where they surface from the skin. Are there any white or gray clumps of eggs? These are actually even easier to see than the bugs themselves. They will be stuck to the feather bases and be hard to remove. See any of those? No? Then they are free of lice at this time.
Mites are a bit more challenging to see because they are active at night, so you need to use a flashlight to check for them. They are also tiny. They look like specks of reddish brown dirt, but they move around. They will also be visible on the skin. Check carefully around the vent area for these as well. If you see none of those, then you are in the clear.
Good luck. I hope they don't have any bugs.