I agree here as I’ve now watched many videos on dubbing and had to perform minor surgery on a hens comb this spring.I am not a vet. I have never dubbed a chicken. But I delved into the world of YouTube to see what most people say about how they dub.
It does seem medically necessary for the poor fellow. My biggest concern is blood flow. Why did his comb grow so big? I don't know the answer to that but with it being so large I would be concerned with high blood volume.
In most of the videos I watched people used very sharp scissors. Where the comb is cut seems to be breed standard or personal preference. If it were me I would plan ahead. Even mark a line on his comb to give myself an idea of where I want to cut. Clean everything thoroughly. Be overly prepared for bleeding. In most videos people had flour on hand. I would have something to slow bleeding. Flour, corn starch, styptic powder. Have plenty of towels. A helper would be, well-- helpful, but if not you can do this. I'd wrap him up snug but not too tight and commit. Don't start and stop. Remember you are doing this for his health. You may need to keep pressure on the wound. I wouldn't pinch the comb itself but downward pressure on the cut.
I hate to say it but be prepared for the worst case scenario of him not making it. I think he has a good chance of surviving this but things do go wrong. At least you would know you tried and he wouldn't be suffocating slowly from his comb being in the way.
Good Luck! You can do it! Keep us posted.
I would sincerely suggest the use of brand new scissors. Yes discard is a good and reliable brand. The kind meant for sewing or crafts, with a comfortable handle that fit my hand well and blades of generous length so as not to have to “snip-snip” but that could do the procedure entirely (or nearly so) with one smooth continuous squeeze. Sewing Scissors are catagorized with different type blades in fact.
Some are meant for very delicate or lightweight fabrics (silks etc) and others are meant for heavyweight fabrics (denim, Upolstery etc).
With scissors I see many advantages, first being leverage, and also very important is safety. Not only to the bird for a smooth and clean cut, but for the person doing the dubbing and anyone who would be assisting.
I respect those who choose to use a razor or scalpel blade but it does seem dangerous and seems to need several swipes to achieve the end result, especially with a bird with headgear the size of yours @Saaniya and @connectdave .
In my opinion, sharp scissors seem a more humane choice especially to someone inexperienced with a procedure of this magnitude.
When I stitched my hens comb I was struck how very tough and fibrous the flesh of a comb is and would suggest practicing cutting some kind of uncooked meat or fish with a pair of kitchen shears or other scissors (but not the actual pair you will use for the procedure, so as not to dull the blades)
This would help you to become accustomed with the feel of cutting through something tough because it will most certainly not feel the same as cutting fabric or paper.