We have 8 sex links and 2 buff orpington, 2 buff Brahma, 4 silkies. We purchased our sex links a week before we brought our other ones home. I noticed a day after the new ones came one of my sexlinks started "sneezing". Then she'd look like she was trying to "swallow". She does this periodically. The next day I noticed a second sex link doing the same thing. The "sick ones" have kind of a wet sound. They don't have a smell. Their neck has a bulge under their beak and it's firm. We give them medicated mash, fresh water daily and we use shredded paper (from my husbands work) as bedding. I called the place we got the new ones and he said none of his chicks/chickens are sick. What could be wrong with them? Should I give them antibiotics? We plan on changing their bedding today. (thinking it could be dust from the paper). Any advice? I love my little babies and would hate to lose any of them.