Hi,
Of course they are edible. There are a lot of variables to your question. For example, I butchered an 18 month old BR rooster that became more than a nuisance and a real pain - if you get my drift.
I can't remember for sure but I think I boiled him, then boned the meat out, & then simmered that with Wild Rice dressing. He was superb.
WRT to Teachers post below, keep in mind that is likely not true of all EEs since EEs are crosses. Some call them mutts but that tends to have a derogatory connotation so I call them crosses or hybrids. How much meat you get is going to be solely dependent on what was used to make the EE.
I made my own EEs this year by putting my Blue Wheaten rooster over a couple of my Welsummer hens. So far I am surprised by the results.
God Bless,