Hi
@Chelimonoah!
It is very important to keep closely observe your flock every day. Once you notice one is sick or not right they should immediately be isolated in a separate area away from the rest of the birds. This will limit the spread of any diseases or issues.
You should plan ahead and create a small housing pen when such issues happen. This will allow you to also keep a closer eye on their health and further tend to any issues.
Here is an example picture of an isolation area....
Always remember, like the other members have mentioned...it is essential that you follow the vaccination schedule.