Ben South BvetMed MRCVS from The Chicken Vet says:
If you are introducing new chicks to an already occupied run and coop then a full disinfecting programme wouldn’t be worthwhile due to the level of contamination in the environment. As a general rule, however, weekly clean outs of the existing coop with something like Poultry Shield or a general poultry disinfectant should keep most harmful pathogens at bay.
It is also important to ensure that you regularly provide fresh bedding for the birds and avoiding wet ground where possible will help reduce the risk of coccidiosis in the flock. If you have a new coop with no birds present then I’d advise using the Interkokask spray and BioShield disinfectant with a good drying time between each treatment prior to introducing the chicks. This will help to create a good foundation for the introduction of the birds. I would then recommend the same regular cleaning process as mentioned above to ensure that the environment is well maintained.