My 3 week old chicks keep dying

[Dorothy01]

My Family and i are new to this chicken farming we hatched 55 chicks
Three days ago they suddenly started dying we lost one first then another then next day tw are sick today and one keeps spitting what looks like mucus and saliva mixed together we really have been looking into what coulbe the problem but we can seem to find out it keeps getting worse each day and we fear we might loose them all i have attached a video of what the salive looks like please help

 

[Wyorp Rock]

Where are you located in the world?

What do you feed the chicks and how are they housed? Photos of their poop may be helpful.

Can you tell if their crops are emptying overnight?
Where did the eggs come from?

I'm sorry you are losing a lot of chicks. If you lose another, it may be worth keeping the body and sending it to your state lab for diagnostics so you can get on top of this. https://www.metzerfarms.com/PoultryLabs.cfm?affiliate=undef