How bloody is the injury? If it is red with blood they will continue. You should get some blue kote from tractor supply or the like and spray it. The color makes them not peck.
That is pretty close for a heat bulb. Do you have a thermometer you can lay in there on the bedding to see the temp? I laid our meat thermometer in mine since I didnt have another option. I believe you may need to raise the lamp. See of you can put a thermometer down to get a temp.
Is that a heat lamp or just a regular bulb? How far off of the bottom of the brooder would you say the heat lamp or bumb is? At first glance, it does look very low, but it is hard to tell without proper scale. Thanks.