I agree with everyone that they're not usually agressive and the kids will be safe around them.
Womble's idea of taking the kids somewhere to get used to them would be a good one and if it's eggs you're hatching yourself the kids might not be so afraid as they'll see them grow from day one

But, if they're really scared (genuinely afraid and not just saying it

) it might be more trouble than it's worth and a source of constant headaches, battles and tears
We probably encourage our kids to have more 'animal encounters' than most folk do

but if there's any sign of real fear from the kids (no matter how daft it seems to us) we wouldn't push it, it might be silly and irrational to us, but to them it's very real and can leave lasting effects.... My little sister (who's 33) is terrified of
all birds, after a one off visit into an aviery with budgies when she was about 5 - to the point where she'd run onto a road if it was the only way away from a pigeon