there is one left out of a batch that we go the first of Sept.. about 11 weeks ago.
she never really grew, and I gave her to my SIL with the "extra" chick that MM sent. she told me last week, that the chick has just lately gotten all of it's feathers and is doing well - but still only about the size of the other chick. I don't know how long she will live, but is growing extreeeemmmmely slowly.
I think everyone in this section has raised Cornish Crosses. Is the question "Do they live to breeding age?". If so, then most don't. They typically die of heart attacks or stroke. Some will always live to an older age, but typically by one year old they'll be goners.
The CX is an F1 hybrid from two different strains of birds which aren't actually 'breeds'. Then again, there are actually no 'breeds' of chicken anyhow; but some people sure get huffy about the subject.