Is it bad for chicken to be carried around?

We have some Isa Browns, some Barnevelders and some Bantams.
My daughter 8, cares for our chicken but she carries the Isa Browns a lot around, patts them etc. She takes them at the bottom of their wings like a neighbour showed us.
Two of our chickens dies maybe two years of age. Is this a usual age for layer hybrids? Or is this maybe because they are carried around too often?

Catching and holding chickens can be stressful to them unless that individual is used to being a pet.  So it could be shortening their lives by stressing them.  Chickens usually live 5 - 10 years, however they will not lay much as they get older.  Eventually they stop laying completely.

If your daughter wants a pet chicken she should pick out just one or two to make pets of, and leave the others alone, in my opinion.

If you have raised the chickens and your daughter is only carting them around and not being extremely rough them then I would say no. 

Chickens can die from their hearts just stopping.  Two dieing this way is suspicious.... but you still cannot be sure it's your daughter and not something else.  Are they getting to anything poisonous - or maybe swallowing small metal objects?  Have you examined the bodies, cut open their throat and crop? 

Sometimes death just happens - I would enlist your daughter's help in 'watching over' the chickens - being gentile with them and making sure they are happy and healthy.  Anyone around chicken's enough to pet and carry them a lot would be a great first line of defense and care IMO ♥

My daughter and I cannot keep our hands off our birds, from hatching to table a lot of touching, loving and hands on care is done (with includes carrying).  You can tell a huge difference in their personalities, but no distress or illness presents itself.  I would go to check on how my daughter's school work was coming and find peeps and ducklings in her pockets sleeping.

On the other hand, we have never had full grown birds come to us - teenagers, but not full grown.  Wild and free animals can suffer great stress at abrupt contact with humans, as Ludi points out. 

We didn't buy them from a breeder, it was just some private guy. From the egg size and their look, they where not quite young, but still I guess not more that two years (We will never do that again). I don't think that they are stressed, because the Isa Browns don't mind being patted. Our rooster is not a real gentleman, but we have enough chickens for him. I am quite happy that you don't think it is the patting because our daughter loves playing with her chicken and she is the one that realizes if something got wrong.
They have got a huge run but they always could have swallowed something. Both chickens died within some weeks they just got slower and dropped the comb and after a week or two they died.

If they didn't seem stressed I would guess the deaths were caused by something else.  I have had a couple of chickens just drop dead from no obvious cause.  I think it just happens sometimes.

Don't know if it's common or not but our chickens will run up and block our path until we pick them up.

Ha! Robert, that's a sign of a tame chicken   

Ours run up, and scrunch down, a sign of submitting to someone higher in the pecking order - much like bowing.

Must be why they do it more for the wife than me, they understand who's really in charge.