I had one like that, and had to cull. The band-aid didn't work, and as the chick grew and gained weight it started to get worse and to look like it was in pain.
Also, a weak chick is more susceptible to illness, and I didn't want to take the chance that later on this chick could cause me to lose everyone.
Yes, kingmt, it's always the favorites or the ones we want most that have issues or get killed. Don't know why, maybe a corollary to Murphy's Law?