Becky, um, clearly you don't know about natures, IV's, and EV's by the way you're talking. ^.^; So, I think I'm going to write a quick guide to help you. It's probably not the best guide out there, and is more like a short explanation than some guide, but it'll do (hopefully).
EDIT: Woah the guide turned out longer than I expected. And it wasn't a 'quick guide' like I said. It actually took a long time for me to make it. And I made it for all of you. :P And I hope it isn't confusing.
And I really don't mean to be mean, but your Unfezant might not actually be as good as you thought it was. ;c It's nature boosts attack, but lowers its speed (it's best stat, besides HP). It's nice to have attack, but because of the drop in speed it probably does more harm than good to your Unfezant. Plus, it might have bad IV's. You said it likes to thrash about, so that means it's highest IV is in attack. Take it to an IV judge, and tell me what he says about it. If he doesn't say 'can't get any better', that means none of its IV's are 31. It probably will have something like 'fantastic' or 'very good', which isn't actually good. I doubt you even EV trained it. Sorry if I sound mean, but I get sort of ticked off when people who consider themselves Pokemon fans don't know a thing about EV's, IV's, or natures. If you actually do, then I apologize.
Natures
These have a big effect on Pokemon. They decrease one stat by 10%, and increase another stat by 10% (however, some natures such as the 'serious' nature don't effect stats at all since it decreases and increases the same stat, cancelling the effects out). To use natures effectively, people get Pokemon with a nature that increases the stat it needs (usually its highest stat to further its potential), and decreases the stat it doesn't need. If your Pokemon has a 'bad' nature, one that decreases a good stat and increases one that isn't needed, it can be harmful and greatly reduce your Pokemon's potential/strength. However, if it's the other way around, increases a good stat and decreases a bad stat, it can further your Pokemon's potential/strength.
For a list of all the natures and what they do, go here. ;D
EV Training
EV's (Effort Values) are points you get from defeating a Pokemon. Every Pokemon gives out one of these when you defeat it, whether it be for speed, attack, HP, or any stat. Many people have no idea about these, and just battle Pokemon randomly. Sure, no problem with that. Your Pokemon will just have EV's in several different stats. But instead of just battling Pokemon randomly, you might want to take advantage of EV's and do what people call EV training, and further your Pokemon's strength. And since many people don't know how to do that, I shall explain.
Now, before I go through the important parts, you need to know that there is a limit. A Pokemon can have a total of 510 EV's altogether. Each stat, however, can only have 255 at maximum. So that means you can have 255 in two stats, or maybe 105 in one stat, 150 in another, and 255 in another. It just has to add up to 510 (well, it doesn't have to, but then that means your Pokemon can still get EV's so it isn't finished). Every 4 EV points your Pokemon gets gives it 1 stat point in a certain stat (depending on what EV's you got). For example, 4 speed EV's would give 1 stat point in Speed, 8 would give 2, and so on. But since your Pokemon can only have 255 points in one stat, the maximum stat points you can get for one stat is 63. Also, you should just give it 252 in a stat rather than 255. Why? Because it's pointless to reach 255 since the extra 3 EV's aren't going to make a difference.
So basically, you want to get 252 EV's in the two stats you are focusing on, and since you now have a leftover 6 points (assuming you gave it 252 points rather than 255), use it for another stat to get 1 point in that stat (I know, not much, but still :P). You might be thinking, "How pointless," but it isn't pointless. An extra 63 points can really make a difference. For example, let's say there are two Pikachu's. The non-EV training one has 200 speed and 100 defense, but the EV trained one has 263 speed and 163 defense. That's actually a pretty big difference.
Btw, some people say level 100 Pokemon need 4 EV's to gain a stat point while non-level 100 Pokemon need more (like, around 6). But I'm not so sure if that's right since nearly every other EV training guide I've read basically explains what I explained.
Anyways, now that you know the basics about EV training, now time to move on to some other stuff on EV's.
Every Pokemon gives an EV Point when defeated. Some give one, two, or maybe three, and some even give EV's in more than one stat. Depending on their highest stat, that's what EV they give. For example, a Starly gives 1 speed EV, a Machop gives 1 attack EV, and a Geodude gives 1 defense EV. And some examples of Pokemon that give more than 1 EV would be Graveler who gives 2 Defense EV's, Seadra who gives 1 defense and 1 Sp. Attack EV, and Raichu who gives 3 speed EV's.
So if you wanted to maximize Speed EV's, you'd defeat 252 Pikachu's (or 255 if you want to gain 3 extra pointless EV's that you don't need). Of course, no one would want to defeat 252 Pokemon just to EV train a stat, and definitely not 504 EV's to EV train two stats. So that's why there are Power Items and something called Pokerus (it's a rare 'sickness' your Pokemon can get). Power Items give an extra 4 points in a certain stat, and Pokerus doubles the EV's you get. So if your Pokemon was holding a Power Anklet (which gives 4 speed EV's), has Pokerus, and defeated a wild Starly (which gives 1 speed EV), it would get 10 speed EV's. The Starly would give it 1 speed EV, then the Power Anklet would give it another 4, so now it has 5 speed EV's. Then, the Pokerus doubles it so it'll get 10 speed EV's. You might be thinking, "Wouldn't that give 6 Speed EV's?" But it is indeed 10. The Pokerus doubles it after the extra 4 EV's from the item is added, so it would get 10.
So then you'd only have to defeat 25 Pokemon to get to 250, then remove the Power Item so that you'd get 2 points and reach 252 (assuming your Pokemon has Pokerus and is defeating a Pokemon that gives 1 point).
If 25 Pokemon is still too much, there's another way to shorten it. Remember those Vitamins, like the Protein and Zinc? They give 10 EV's in one stat. But you can only use it 10 times per stat, so the most EV's you can get from this is 100. However, it is suggested you use these before you start EV training, because it only works until you get to 100 EV's in that stat. So if you already had 10 EV's in a stat, you can only give it to it 9 times.
So, if your Pokemon has Pokerus, is holding a Power Item, and used the vitamins, you'd only have to defeat 16 Pokemon (on the 16th time, remove the power item so that you'd only gain 2 EV's and not gain more EV's than you need, once again assuming the Pokemon you're defeating gives 1 point).
If you found that confusing or have questions, I'd be happy to answer. ^^ Btw, there are special berries that remove EV's in case you make a mistake, and to tell if you reached the 510 limit there is someone who will give you an Effort Ribbon. If they say your Pokemon 'could try harder' or something like that, then you haven't reached the 510 limit. If they give you an effort ribbon, then you've reached the 510 limit.
For a list of Pokemon and what EV's they give, go here. Btw, that's only the list for Pokemon that give HP EV's. If you want to see a list of Pokemon that give other EV's, just click one of the buttons/links at the top.
IV's
Now, last but not least, there are IV's. They don't have an as big effect as the other two, but they are still important. Remember the Judge that tells your Pokemon's potential? He's the IV Judge. I'll explain about him later. For now, I'll explain about IV's.
As soon as you get a Pokemon, whether you bred or caught it, it has IV's that cannot be changed. Caught Pokemon tend to have lower IV's, while bred Pokemon tend to have a higher IV's. However, that does mean you can't get a caught Pokemon with high IV's or bred Pokemon with low IV's. It all about luck (but in breeding it's a little more controllable with the help of certain items).
IV's range from 0-31. 0 is the lowest and 31 is the highest (obviously). For each IV you get, that's a point. So 31 IV's in attack would give you 31 stat points in attack (but like EV's, they get added to your stats slowly so you'd only see the difference at level 100).
Every stat has an IV. Here's an example of what your Pokemon's IV's could be.
HP-29
Attack-31
Defense-25
Sp. Attack-31
Sp. Defense-31
Speed-31
Unfortunately, IV's like that are very, very rare. Getting a 31 isn't easy, and the example I showed you is considered very rare to get, and if you get IV's that good you're very lucky. Since 31's are rare, most people aim for perfect IV's (31) in the stats they need. It's too hard to breed like crazy for all 31's. It's so much easier to just aim for a 31 in one or two stats. But if you think you can do it, I'm not stopping you from aiming for perfect IV's in all stats. I'm just warning you it'll be hard, and definitely time-consuming.
Here's an example of what a caught Pokemon's IV's might be like:
HP-16
Attack-20
Defense-9
Sp. Attack-22
Sp. Defense-21
Speed-13
You might think having a 31 in IV's aren't important, but many people (if you're doing competitive battling) will aim for good IV's, so if you don't care about IV's, then tough luck winning. A one point difference can really make a difference. For example, even if you have only one point less than the opponent in speed, it will still outspeed you. But if you had paid attention to IV's and actually bothered to aim for good IV's, you might have been able to outspeed it.
I think that's it on IV's. I'm tired so I might have missed something, but whatever. At least you know the basics. Now to move on to the IV Judge. Actually, one more thing. It's a tip on breeding for IV's.
Also, here's a tip if you're breeding for IV's: If the parents have bad IV's, since the baby inherites three IV's from the parents (picked randomly from either parent), it'll be nearly impossible to get good IV's. If both parents have at least 3 perfect IV's altogether, that the only way it'll be possible to aim for all perfect IV's (if the baby inherits those three IV's, it'll have 3 perfect IV's, and the rest is random and left up to luck). If both parents have no perfect IV's, it will be impossible to get all perfect IV's since the baby will always inherit three of their flawed IV's. Also, if a parent has a 31 in a stat and you want to make sure the baby will inherit it, make the parent hold a power item (power bracer to inherit attack IV, power anklet to inherit speed IV, etc.) and the baby will always inherit that IV.
Now I'll move on to the IV Judge. The IV Judge judges your IV's (obviously). He will first tell you your Pokemon's potential. Your Pokemon's potential is basically all its IV's added up together. Here's a list of the potentials your Pokemon could have and what the sum of the IV's are.
Decent all around- 0-90
Above Average- 91-120
Relatively Superior- 121-150
Outstanding- 151-186
After saying its potential, he'll say its best stat. If he says it 'can't be any better', it's a 31. Also, if it has another stat with the same IV he will also mention that stat (in Gen V he does, but not in Gen IV). So for example if he says your attack can't be better and he says your speed is 'equally as good' or something similar to that, then they both have a 31.
Rather Decent- 0-15
Very Good- 16-25
Fantastic- 26-30
Can't Be Any Better- 31
I think that's it on IV's and the IV Judge. And in case you're wondering if I do all these nature, IV, and EV stuff, I actually do. Right now I'm breeding for a female (yes, I'm picky about gender) Jolly Bagon with a 31 in attack, speed, and special attack. Everything else I don't really care about as long as it's 20+. The parents of it have good IV's, the mother is holding an everstone, and the father with max attack IV is holding a Power Bracer so the baby will always have max attack. Because one of the parents (the mother) is holding an everstone, there is a 50% chance the baby will have the same nature (and the mother happens to be Jolly, so the baby is likely to be Jolly). Plus, it will always have 31 attack IV because the father is holding the Power Bracer and has 31 attack IV. The rest I just leave up to luck, and hope the baby will also inherit the mother's 31 speed IV and the father's 31 Sp. Attack IV. c:
So... yeah. xD I know none of you really needed this guide, but I was bored so I decided to type up this whole guide to help all of you and so I wouldn't be bored. Anyways, I hope the guide helps. :D