If you are soon going to hatch another brood you'll have to take extreme care to avoid cross-contamination, as cocci is so very infectious. As they can't go in together, you will of course need a second brooder and a separate set of equipment for the second brood, and preferably keep it in another room. Always scrub your hands after handling one brood before moving on to the other, and take great care to sterilise feeders and drinkers every day. Try to create a really absorbent floor and bedding for them - line the brooder with several layers of newspaper, topped off with soft absorbent bedding of your choice, either cotton layers as I mentioned, or wood shavings perhaps. The danger of infection is much greater in the presence of a damp floor, because the heat and humidity in the brooder will spread the infection. Also, as you know, they are terribly messy little things, scatter food all over the floor, poo in it, and then eat the food which is contaminated with cocci oocysts. If possible wih your heater, reduce the heat a little every day, once they begin to feather up, which they do very fast as you know. Cooler conditions will help harden them off and infection will be less able to take over. I think the main thing is to sort out the drinker, thus reducing the risk of wet bedding. The best disinfectant for cages and equipment if cocci is suspected or diagnosed is called Bi-oocyst, which is the only one that will effectively and safely deal with the microscopic oocysts which are shed by infected birds and passed on to the others. It's potent stuff, use only with care and wear rubber gloves. Wipe the heater and all round the cage, as well as cleaning up all the equipment, and repeat the process regularly when you change the bedding.
You might like to consider changing to medicated chick crumb, at least for the second hatch, rather than giving them Coxoid. But don't do both!
There a good article on coccidiosis on the main Poultrykeeper website, https://poultrykeeper.com/digestive-system-problems/coccidiosis-in-chickens/
There's a link to this invaluable site at the bottom of each page on the Forum.