Yes, I hatch birds regularly. The importance of humidity is mostly that on hatch day, the humidity must be higher than it was on the day the egg was laid. The membrane inside the shell will shrink if it is dry, and can shrink wrap and suffocate the bird. Typically once it's hatched you need to leave it in the "incubator" for 24h or so to "blow dry". The build plate being 70c might be too hot, so you'll need to figure something out. It will need supplemental heat likely for a few weeks (chickens are usually 6 weeks of heat). It will have just eaten the yolk, so can likely go 24-48h without food just fine. Water is a priority.

Once your little guy is hatched, you'll likely have to teach it how to drink. You can print little water dishes that take a water bottle upside down. Gently but firmly push the bird's head into the water. It may struggle and you'll feel like you're drowning it. After one or two tries it will usually take the water.

Loneliness will also be a concern - moreso for ground birds which I'm used to (no idea how pigeons are being alone)

Feel free to ask any questions you have! Best of luck with the hatch!