Chicks have 'bumps' on their heads! Need HELP!?!?!?!?!?!? (PICS!!)

[kainat parvez]

So...I went to the Mothers Run today to do a check up on the food, water and the chickens and then when I got to snowballs chicks I noticed that they have got little 'bumps' on their heads and I don't know what it is and if it is okay to leave them alone?
I have added some pics, but they are not the best - SORRY






This white Roo chick has the biggest 'bump' of them all!



These are not all the chicks (that would have been too many photos) but the 'bumps' all look the same!
Can you guys tell me what you think or how it went if you have experienced this before! I really don't want to lose them because they are my favourite chicks!

what Happen to my chicks can anyone tell me this pleases
I don't know about this and i really want to help him