How do I prevent burning when searing in batches? Often, recipes require you to brown meat or pan sear meat. When working with large amounts, how do you prevent any of the bits that stick from burning?

A practical example: I marinaded chicken breast fillets with Chinese five spice. Whilest pan frying on a cast iron, pieces of chicken got stuck. Since I had to cook in multiple batches the pieces that got stuck eventually got burnt and ruined any possibility of using the fond (of course, you probably wouldn't use this fond, but this happens with beef too).

I want the cast iron to be hot for a nice browning but raising the temperature inevitably makes any stuck pieces of chicken burn even faster. Oil helps to a point but I don't want to use too much. Cleaning the cast iron becomes a pain because now there's charred patches that are rather hard to properly make out on the black surface. Any ideas?
Using slightly lower heat helps, but if you have several batches to do, mostly it's best to scrape/wipe out the pan between batches.  I would not use cast iron in this case, as you point out, it is difficult to clean quickly.  The fond can be scraped onto a plate and used at the end, alternately, the fond from the last batch can be used.