Based on its phylogenetic position, John Foster (2007) inferred that the feathers of Ornitholestes would probably have been more primitive than those of birds; they likely "would have covered the body except the legs in a short coat, perhaps with longer feathers lining the top of the skull or neck and the back edge of the forearms."
Na osnovu njegove filogenetske pozicije, John Foster (2007.) je zaključio da bi perje kod Ornitholestesa vjerojatno bilo primitivnije nego kod ptica; vjerojatno bi "perje pokrivalo cijelo tijelo osim nogu kratkim ogrtačem, možda sa dužim perjem na vrhu lubanje ili vrata i na stražnjem rubu podlaktice.