Simple.. He is just exploring his hands. Its basically hand and mouth co ordination and your baby is practicing it and it is a good sign. Many people say he/she ia hungry if they put hands in the mouth. Just relax. Keep his hands clean. It is a phase.

while feeding he prefers sucking his hands rather than milk...what does that mean?

This happens and is normal. try and keep a silent and calm environment  to minimise distractions.

baby do this in thr age, try to keep the environment calm and silent while feeding switch off the lights , it will work

Its quite normal <span style="color:#3B5998;"><b> @616da041202a1a0013095812 </b></span><span style="color:#3B5998;"><b><u></u></b></span><span style="color:#3B5998;"><b></b></span>. And after a month, they will suck for sometime and started holding your chains and will see here and there if they hear even a minute sound. Feed your baby on demand. Afterall they are exploring their world&#128077;&#9786;&#65039;