The most important thing is to make sure you know were the birds are coming from….
If bringing in new birds from another loft aways isolate them for 2 weeks so you don’t introduce sicks birds.  Birds that are sick don’t always look or act sick, nature tells them to look well so they are not picked out for pray in the wild.   Birds from a pet shop are the worst of all to bring home, the biggest carriers of diseases come from pet shops.  Always worm birds from the out side.   Young birds tend to pick up diseases from other birds as they don’t have a lot of immunities built up in them.  So if you end up getting some sick birds it will be your young ones.