How to differentiate RIR and Buff orp chicks? BO chick with black head markings? Help!!

[Kearaaaa23]

Hi everyone,
I just had a batch of chicks hatch today. I have 1 buff orpington amongst 7 or so RIR chicks. And literally cannot tell which is which now. I need this buff orp chick for an order and cannot afford to mess it up. I am happy to send pics if needed but they all basically look identical. Here are some pics. I speculate that chick #2 is the buff orp cus she has whiteish feet, is broader in size and has a slight yellow tinge. However she has some black markings on her head and isn't a solid bright yellow but she is closest to the breed "standard" from this batch. Spoke to the seller and she claims they are 100% buff orps. Please help!!

 

[oldhenlikesdogs]

A buff Orpington should be all over a yellow color, and a Rhode island red should be darker on the back and lighter on the stomach. Feet color may be similar at that age with the Rhode having a bit more orange coloring to them, and the Orpington more pink. There shouldn't be a head marking on either breed.