My grandson was in an in home daycare and there was a baby whose mother brought organic food for him. The care taker did react as you suspected one might. She thought it was a bit of a hassle and a bit silly but she did feed it to him.
It wasn't a problem with other kids noticing he was different maybe because he was a toddler and the other kids were preschoolers.
This caretaker provided healthy snacks. She was licensed thru the state and thus was required to provide healthy snacks. She had to file a report listing what she'd given them. She gave them crackers, fruits and veggies tho not organic ones.
If it's important to you that he eat organic, talk with the caretaker and ask what she thinks of it if you bring his snacks. You could bring something similar to what she serves.