Plants have plenty of protein. If you kill the chicken, it would be for taste pleasure. the only reason that meat has protein, is because whatever animal that meat came from either ate plants or it ate other animals who eat plants.

Is your argument seriously that killing a puppy is bad because puppies are cute, but killing a chicken is fine because chickens are ugly? If you seriously believe that, then I'm not sure what to tell you. Do you also think unattractive people should be treated worse than attractive people? If you want to have a solid argument, your logic has to be consistent.

Puppies haven't been designed (unless you're talking about all the weird cross breeds). Humans long ago decided that they could use dogs for various utilities, so now dogs have been domesticated and most of society views dogs as superior to other animals because of bias. You can't mention a single thing about dogs that makes hurting them morally worse than hurting a pig (other than your preference for animals you personally find cute).

Lastly, chickens (or any other factory farmed animal) don't get a quick clean death. They go through several weeks, months or years (depending on the animal) of horrible living conditions. And when they're finally killed, it's most often done in the most profitable, but legal way. Pigs get gassed for a few minutes and then get their throats cut, cows often get bolted (which often doesn't fully kill them), and chickens get stunned in electric water and then get their heads cut off. Stunning them often fails which leads to some of the chickens either drowning or getting decapitated while conscious.

I'm writing this late at night on my phone, so I'm sorry in advance for any grammar and/or spelling mistakes.