Hi there.
Sorry you are facing this.
Are these chicks being raised by broody's or inside a brooder? Hatched at your place or from somewhere else? Have you ever had a Marek's diagnosis at your place or in your flock? Are any of your birds vaccinated for Marek's?
Are there any noticeable symptoms or behaviors aside from the lameness such as ravenous appetite or none? Any change to pupil shape or iris color in the eyes? Change in droppings? All one breed or many breeds of bantam chicks, which?
What do you feed including treats and supplements prior to noticing this condition? How long has this lameness been popping up in your chicks already?
What have you done to treat the lameness and what have your result been thus far?
ETA: Are you able to post a video?