The best jumpdawg I ever had never started till a year old(Sharp Mikie X HH PopFannie).
Some are so keen and beyond their years they blow up.
I'd give 4 years to get a great one that could do it all. Showing progress and the ability to adjust and learn from mistakes. Hunted her till she was 12, then she started doing stupid things, a very sad time.
Many people have sent their northern hounds south to get a start on cottontail, they learn patience and line control from the sitting, twisting rabbit. Many have said their best hounds were started in this way when returned to run hare.
One thing I learn't from the hare bred was their natural tendency to range wide while hunting. I learn't them to hunt closer as puppies by changing directions on them often while they still had the need to know where I was and were unsure of themselves. When I started running hare, I learn't why they wanted to range naturally the way they did, a hare hound has to got out and hunt, ranging much like a bird dog to start it's game...else, your going to be doing a lot of walking...
I've had a couple of cold trailers years ago, did a good job and were dependable to start their rabbit but not what I liked as nobody would hunt with me. Medium/slow, you could hunt a 20 acre patch all day. My grandpa like them as he could sit on his stool and it was slow smooth music and the rabbit came through at a rate where even a 12 year old boy could shoot it...
They would have been useless on deep snow as they had not the constitution to tackle work in deep snow, they were better a rooting under honeysuckle and dead falls.
I remember reading in the old books that in the latter days, the Blue Caps of Mr. Card had become slower and apt to cold trail a good bit. It was offered to him to come down to the Northern Hare Trials and see hounds that could run and punish their hare...don't think it said whether he ever made the journey or not.