In general, the condition of the frogs is going to determine which route you take with quarantine. If the frogs are in poor shape or are wild caught animals then initially it is often a good idea to provide them with a quarantine enclosure that allows for security (in other words not a bare enclosure). Once the frogs have settled down a little and are feeding okay, you can then move one or more of them to a shoebox lined with unbleached papertowels and some hide areas (I use the smallest plastic hides for snakes) to collect a fecal. The frog can then be returned to the enclosure while the fecal test is being performed. If you use something like one of the plastic gasket containers with ventilation (as these can be made fruit fly tight easily) then when you just move the frog to the next clean container and the previous one is cleaned and disinfected. This way if/when you have to treat the frog(s), you can treat and move them to a new container to keep from reinfecting the frog. Minimum quarantine recommendations by institutions is 30 days or three clean fecals taken at least seven days apart which ever is the longer time frame as this gives the best picture of whether or not the frog requires treatment for a parasite/parasites. If the vet can see the actual frog in hand, then depending on the parasite some vets may decide to not treat if the load is low, if they cannot see the frog, then the vet is going to be more conservative and require treatment. Some vetran keepers do not consider a wild collected frog well adapted to captivity until it has been in captivity for at least a year.
If the frog is captive bred or well adapted, then they tend to do okay in sparten quarantine enclosures but again, you need to be able to shift the frogs to the new container while the old one is being disinfected.
When collecting fecals do not place plant cuttings or leaves or other organics in the box with the frogs as these can lead to false positives for nematodes and some other oddities. If you do collect from an enclosure with those materials make sure the vet (or person reading the fecal) knows so they can account for false positives.
As for prophylactic treatment for chytrid, this is problematic as ideally any unnecessary treatments should be avoided but chytrid is a risk. Keep in mind that chytrid has not been shown to be lethal to frogs that are kept above 75 F. Below that temperature is where we see deaths due to chytrid infection so if you want to get them tested, you just need to keep the frogs above that temperature until testing has been done.
Ed