Hi Deb,
Rain is always an issue when medicating birds in their drinking water.
You've got 2 options, depending on the weather conditions.
The first is to extend the treatment period to say 10 days, then repeat in 2 weeks.
If the wet weather has set in and will last more than a few days, you may be best to quit treatment at the end of your 7 days & try again later when it's drier. There is no harm in treating when it's wet. At worst it is ineffective. At best, the birds may still drink enough to suppress the coccidia, but you are likely to have to repeat the treatment.
If you were just treating on a routine preventative basis ( rather than treating an existing problem), then I would stop now and wait for the weather to dry up- then start again.
It is very difficult, if not impossible, to totally eradicate coccidia from any bird. What you are aiming to do is to drastically reduce the numbers to non-pathogenic levels by medicating and by boosting the birds' immune system through good diet, housing & low stress.
Keeping floors dry helps to decrease survival of the infective cysts in the environment.
Low numbers of coccidia can allow the bird to develop some immunity to the organism so that it can deal with the problem itself- almost like self-vaccinating if you like.
As for the birds in the suspendeds, they are less likely to reinfect themselves since they don't have access to their own droppings and are not exposed to damp floors.
If any sick birds have been found in the suspended aviaries then yes, by all means, treat them. Or if they have recently come from conventional aviaries which housed other infected birds, then I would also treat them. Otherwise it is less likely to be a problem. If you want to make sure collect a group faecal sample from all the birds housed in suspendeds, have them tested by the vet which should give you your answer.
Hope all the waffling helps & doesn't just confuse!
Cheers
Myzo.