Poopy Vent Feathers and sneezing

[Augie1]

For the past couple weeks a couple of my chickens have been sneezing like in the video. Should I be concern? I'm currently deworming them with Valzaben and also using treating coccidiosis Friday will be there last day on Corid. 3 of my chickens have poopy dirty vent feathers. Should I be concerned?
Thanks

 

[Wyorp Rock]

Replies are on your other thread.
https://www.backyardchickens.com/threads/accidently-submitted-it.1424268/