I've been in this situation already and took the crippled doe. That same season, I also purposely hunted all season for ANOTHER crippled doe. She eluded me the entire year even though I had her almost with-in bow range a couple times. She was very smart and capable despite her crippled back leg. I even watched her spar with a buck during the rut. She put her head down to challenge him and then pushed him around! He gave up!

I usually trophy hunt when I'm after bucks, but when a crippled deer comes along, I will change my own rules.