i raised ten cx's this spring in a tractor, i can't imagine doing three hundred, with just ten i thought the mess they made was nuts... but anyways, i finaly got sick of them sitting around in my basement and threw them out, i didn't bother to write down how old they were and have since forgotten but they were pretty young, probably too young to go outside. especialy outside into a new england spring. i think it was around mid-late may and the day i put them out it was 65 and sunny, that night it dropped to 45 and started pouring, didn't stop for 5 days straight, literaly. and i never lost any. as for tractoring them on snow, doesn't that kind of defeat the purpose since all of the vegetation will be covered up and bugs will be gone, also cx's just don't strike me as a winter hardy breed, maybe another breed.