Jorund, your plan appears impracticable in view of what the others are planning to do, apart from the “throw hammers” part. However, casters can usually see what they’re doing through the rank in front of them.
Ivar seizes the opportunity to Bless himself and his comrades as it must be cast before battle is joined. Ulf, Bjarni and Jorund launch a volley of missiles at one of the larger owlbears, it collects no fewer than four arrows but is still going. Jorund’s hammer glances harmlessly off it. Osvald looses off another Flaming Sphere hoping it will be more use in these confined quarters.
Thus provoked, the angry critters charge. Ivar looses off his javelin, dropping the wounded owlbear with marksmanlike precision. Ulf and Bjarni again hit twice with their bows, felling a second “adolescent”, and Jorund’s second throwing hammer catches another one dead centre above the beak. Choosing his moment well, Osvald catches the onrushing group in a Colour Spray and four of the smallest randomly chosen fall unconscious. The injured one attacks Ulf, beaking him for 5 damage - he is now down 19. The largest left attacks Jorund, clawing him twice for 7 (down 20) and one of the small ones claws at Bjarni, easily repelled by his shield and armour.
Both berserkers go berserk, seeing there are still plenty of foes and they are taking damage, but Jorund holds back the Aspect of the Storm.
Thinking quickly, Osvald rolls his Flaming Sphere over the unconscious owlbears for maximum effect. It is not big enough to do full damage simply by sitting it in the middle of them. Ulf slays the creature before him with one blow of his mighty poleaxe. Bjarni fences expertly with his, Jorund smites his with both hammers and (amazingly) it is still going…! Ulf gets clawed and bitten by the onrushing “juvenile”, it tries instinctively to hug him but is too small to do so effectively. He takes 9 damage anyway for a total of 29. Jorund easily ducks the creature fighting him but Bjarni is saved only by a reflex parry with his shield. Ivar, seeing Ulf getting badly beaten up, touches him with a 10-point Cure Light Wounds to leave him a mere 19 in arrears.
Osvald reverses the direction of his Sphere putting the finishing touches to the unconscious owlbearlings, and it then goes out. Ulf hits his new opponent - a mighty blow by most standards, but a mediocre one by his - Bjarni misses, and Jorund spreads his wounded foe over quite a large area. Bjarni is the only party member to suffer a counterstrike and that a mere scratch for 3 (down 15). Both berserkers have fresh foes by the end of the round and Jorund hits his hard, but not quite hard enough.
Ulf disposes of his last foe, Bjarni trades blows with his and feels that one more hit point is not a bad trade for killing it where it stands, at that. He is now down 16. And in a blur of total carnage, Jorund and his owlbear exchange five successful hits between them in a vicious hand-to-claw struggle that sees the creature slain but Jorund taking a further 10 from the little varmint (down 30). Then, to his everlasting joy, Osvald plants his long spear in the way of the last onrushing juvenile and drills it cleanly through the heart. Even wizards get lucky sometimes - besides, it’s the weapon that he wields on the fighter’s To Hit table. 
Whereupon the Bless lapses, the exhausted Berserkers come out of their rage, none of them quite falls over, and you are in sole possession of a largish chamber which makes Woolverton town square smell like a perfumier’s. A little judicious exploration reveals a still smaller chamber with a floor carpeted with rushes, although they have a farmyard stink to them. In there you can see three very small owlbears about the size of young bear-cubs, some shards of eggshells, and two large eggs. There is also a raised platform in there about three feet off the floor and made of wood, about six feet square with a slightly raised edge all around. Watching the hatchlings, you are able to see that they are no threat to you - their claws are undeveloped and their beaks don’t appear to be fully hardened.
