Those seem like either sneezes or he has something kind of stuck in his craw. I've had a hen do something similar, or who was a bit wheezy, and it ended up she had something in her throat that she had to work out. I'd maybe try to encourage him to drink, or give him some wet food to see if that was of interest and might help him moisten/swallow down whatever it is. You might also search for sneezing here, and look for any further respiratory symptoms appearing (in which case I'd separate him and put him some place comfortable/warm with food and drink and make sure he was eating/drinking - but I'm not had respiratory illnesses to deal with).