That poor guy looks completely embarrassed I don't see any reason he NEEDS to wear the jumper (though this would have been perfect for a nearly bald frizzle I used to have).
Nikki
These are usually used for rescued Battery Hen's who don't have any feathers or have boo-boos that are needing to be hidden......or just a really ugly molt. LOL There's quite a few sites that offer freebie knitted patterns for them.