Yes, they will. They will test for whatever you ask them to. Kudos for thinking like this! thank-you for posting back, I am happy to hear about the EE. How much of the Bs are you giving and is it the Super Bs? Reason I am asking is she may be able to be weaned from them slowly. I had a couple that had to have a full Super B Complex in a gallon of water everyday for months. Well one day, I only had a half pills left because of treating others. Well I gave it to them and hoped for the best, until I could get out to the store. It worked. No problems at all! So I continued with that for a week and then cut it back to 1/4 of a pill. Same results. I did this for a few weeks because I am a Nervous Nelly when it comes to making these decisions, lol. Finally, I stopped them, there was no change in them at all. This may or may not work for you, but it might be worth a try. If you see any indications things aren't working, put her right back on them. She may have a defect that doesn't allow her body to metabolise the Bs from her food or it could also be the C included in the Super Bs. Don't know.....I think of it this way...if it ain't broke, don't fix it. I don't always need an answer as to why something works, either because there is no time to figure it out or I am unable to. I do try to find supportive research being done or already done, but sometimes there just isn't any. Sometimes we who have, are doing things not tested yet or even thought of. We just 'Do' and watch for results. Lol, sad thing really, you can't mess up with a Marek's bird. The prognosis is always the same in the end. It just comes down to when and quality of life over quantity.