Leno and Hobler,
Yes Hens grow on Oaks only. Never found one on anything but an oak. They grow on Live Oak mostly and sometimes dead oaks. They are firm and meaty and pick when fresh. When they get huge and old they get tough and can smell. So a young hen can still be 25 lbs or more. A hen is fresh when the mushroom is white underneath and smells good and bug free for the most part.
There may be some beatles in them now and then or even ants. Just cut them up in quarter slabs and knock them on the table outside a bit to knock the bugs out if there are any. Sometimes there may be a pill bugs or centepeds in them too. However when really fresh not as many bugs.
Store the hens in plastic bags in the frige un-rinsed. Rinse them in cold water in the sink just before you prepare to eat them. They saute up great in olive oil or butter. Cook until golden brown. They hold up great in Spaghetti sauce, Alfredo sauce etc. You can pre-saute them for 5 minutes or so prior before putting them in a sauce. They are great diced up on a pizza too. You can pre-saute them for 5 minutes and then put them on the pizza as a topping.
The entire part of the mushroom is edible. The floret's are most desirable. However the big white meaty core is great too and can be sliced or diced up to use in a sauce or for saute.
Good luck fellas.
Latt