Sorry to hear your birds are feeling ill.
Do you have a video of the birds sneezing? To post a video, upload it to a video platform like Youtube or Vimeo, and copy/paste the link here. Is there any swelling around the hock area? Are they eating, and drinking well?
I don't have any experience with Turkeys, but will see if
@casportpony , or
@R2elk may be able to help further.
Facial edema and swelling are both good signs the birds likely have a respiratory disease of sorts. Mycoplasma Gallisectum often causes facial edema and is a common respiratory disease in turkeys. There is no cure for MG, oftentimes, the owner either euthanizes the birds, and starts over, or treats them with an antibiotic, such as tetracycline, or a fluoroquinolone such as Baytril. If you wish to treat them you can find both of the drugs here,
https://www.jedds.com/shop/tylan-soluble-100-g/
https://allbirdproducts.com/products/baytril-10
As I said earlier, the antibiotic will help alleviate the symptoms, but during times of stress such as cold weather, or molting symptoms may reappear. Over time the effectiveness of the drug may decrease, and a new antibiotic may need to be set in place. Keeping their coop clean, and ensuring there is adequate ventilation is important if you decide to treat as well.