NEED HELP!!

i think my pigeon is ready to lay eggs. so i put some twigs inside the cage. i found the male pigeon taking the twig and placing it where the female pigeons is standing. and female pigeons keeps moving and now the twigs have been spread all over the cage. i also found the female always lays down. is this the sign that she is pregnant and ready to lay eggs??

Females start lying down when they are ready to lay eggs, so I think you're right. She will lay one egg, usually in the evening, and two days later she will lay a second egg.

Don't worry about the pigeons scattering the sticks. I have a couple who do that all the time, they never seem to agree where they want to make the nest. I just give them lots of sticks and straw and let them make a mess with them!

VERY IMPORTANT: At egg laying time, females need lots of calcium, or they become very weak, can't stand up, and the egg may break inside her, killing the hen. If she doesn't have pigeon grit (a mixture of coarse sand, oyster shell and some minerals pigeons need), in an emergency you can boil and dry some egg shells (chicken eggs are fine), then crush the shells into very small pieces and give that to her in a dish. She'll need that to produce good eggs and to stay healthy.

ok.. i giv them wheat and moong bean. is this ok?? And also note iam from india, and these are indian pigeons. so eating habits will vary, right??

Yes, eating habits will vary, some of the grains you have there will be quite different from the ones I get, but I wasn't talking about food.

Grit is not food, it's little stones (the size of large pieces of sand) mixed with mollusc shells and minerals, so that the pigeons can have the materials to make the egg shells. This is very important for laying hens, and without it the eggs may break, or the babies and the mother could die.
If you can't get pigeon grit try at least my suggestion with the chicken egg shell, that I posted above.

ok... but when i open cage i hav found the female and male eating sand and stones.

That may not be enough, it depends on what composition the sand and stones have.

will the female start eating more if she is ready to lay eggs? and also will she produce any special cooing sound ?? is laying down in cage most time, a sign of pregnancy??

I know somebody who would be brilliant at advising you about your pigeons and eggs, especially because he's in India like you, and he's very experienced at raising birds. He's Dr. Boney, from Kerala, and this is his website, that he created to help people who are just starting to keep pigeons.
Here's his link: http://godsownloft.webs.com/ I hope that helps.

thanks a lot..