I am not an expert but they have a heritage bird "build" but the color is that of a Commercial white. They could be a cross. The would be my best guess. I wish I could do it for ya! I like to doctor! You will too after you do it a few times and gain some confidence. If you post a photo tomorrow I can help you pick out a place to make an incision. I am new to this forum... am likely to be around until the sun starts staying up longer. Then the 14 hour days begin! I won't leave you hanging. : ) Having sick critters is NO fun! You might also consider a medicated feed. If you want to hit this at all angles. If you don't have medicated feed - a table spoon of yogurt each day for a few days will help. Mix it in it's feed. (or raw goat/cow milk if you have access).