The primary requisite in a heavy duty knife is stoutness. You want something that will not only hold up to but thrive on what would be massive abuse to any other knife in your set. You want something heavy, tough, and which can seem reasonably sharp when sharpened to obtuse angles.
What you want most is tough and easy to sharpen. Hardness is counter-productive.
There are a few schools of thought.
The Western Deba
I've never met one I thought was any good that was at all affordable. You don't don't need a lot of hardness, you don't need a blade alloy that will take a great edge. Fortunately that lets the expensive knives out of the running.
You spend time in Japan and have access to all sorts of knives not usually available in the US, so maybe you know of a reasonable quality yo-deba at a good price. I don't.
The Old or Cheap Mongo Chef's
If you're only splitting chicken, portioning ribs, and the like you can use a 12" chef's effectively. Almost any 12" chef's will perform well enough as long as you sharpen it appropriately; which, by the way, is fairly obtuse, and none too polished. A double bevel is good if you can do it.
New, cheaper knives to consider include, the 12" Dexter Sani-Tuff, the 12" Forschner and even the 14" Old Hickory butcher's (that one's a beast to sharpen, though).
If you can find a used, forged, German or American -- whether F. Dick, Henckels, Lamson, Messermeister, Sabatier (even of dubious heritage) Wusthof or whatever -- those are great. Weight counts more than quality. Keep your eyes on e-bay.
When you're at the flea market, remember (it's worth repeating) weight counts more than quality. If it's long, heavy, cheap, not too chipped or bent, the handle's in good shape, and you think you can sharpen it -- you've found a winner.
I use a 12" K-Sab au carbone, sharpened to a 25*/17* double bevel (sharpened freehand to an approximation of that anyway -- freehand numbers are sort of wishful estimates). Double bevels are stronger than singles.
Chef de Chef
These are European chef's knives expressly made for the purpose. They're a lot like yo-debas -- are probably the prototype for them in fact. Oddly, yo-debas of similar quality are more expensive. That's probably because they use more expensive alloys -- which are wasted for this purpose.
Speaking of expensive, Forschner makes a rather expensive heavy-duty chef's which is a very good knife. Recommended if you can find it sufficiently discounted. Don't go over $130 for it.
There are a couple of carbon Sabatiers, sold as "chef de chef" running about which would be ideal. Google the term, and you'll find The Best Things, but some other places too. All things considered, those are fairly reasonable. Go figure.
The Meat Cleaver
By meat cleaver, I mean meat cleaver and not a Chinese cleaver, Chinese chopper or Chinese chef's knife. Those are all much lighter and relatively easily damaged.
There are some excellent, heavy duty cleavers around for under $40. They're tough. You can pound on the spine with a hammer if you need to. You can use the flat for flattening. They're usually hard to sharpen. They're usually too short. Shortness more than anything has driven them out of favor.
I own a great, mid-sixties, carbon Chicago Cutlery cleaver and almost never use it -- instead almost always going for the big Sab.