Um...
I think you are confusing yourself with IVs and EVs.
The power items can be used to max a PKMN's EVs.
IVs on the other hand are like a PKMN's DNA. You can't increase or decrease it. =/
No, I think I know what they're saying. The Power Items do in fact pass on the IV to the offspring (so for example, the Power Bracer, while in battle, makes the Attack stat grow faster, when held while breeding will always pass the Att stat of the holder onto the offspring. This is true of the various stats of all the Power Items) But to get to the original poster's question:
Ohhhh I see what you saying, the destiny knot must have selected all the Ivs that were at 0, so its better to use the power items for the first few eggs til you get the mother with 4 or 5 IVs then use the destiny knot?
Also it is possible to have all 6 IVs maxed out right? Does it take a long time to get all 6 maxed out?
No, this is not correct at all. the destiny knot didn't pick stats that were at 0, it picked stats that were not maxed (Ivs range anywhere from 0 - 31) The Destiny knot picks 5 stats randomly from either parent. Every egg the destiny knot picks new stats at random. Even with a parent with 6 IVs and another parent with 5IVs you can STILL get offspring that are 4 IVs. (Because the destiny knot could pick the one stat form the 5IV parent that is not 31, and then the 6th stat will always be random) the power items don't help much at all because while they do pass on whatever stat they raise, they ONLY pass down that one single stat. The rest are random.
When breeding with no items, the parents can pass down 3 IVs randomly chosen from either parent and the other 3 stats are randomly generated (there's no rhyme or reason to what stats are chosen and what aren't) the power item simply fixes one stat to be passed down while the other two are randomly chosen, and then ofcourse leaving the remaining 3 to get randomly generated. With the Destiny Knot in the mix, 5 IVs from either parent are randomly chosen, and again, each egg has different stats chosen each time. If you give one of the parents a Power Item, that stat is guaranteed to be passed down while now FOUR IVs are randomly chosen from the parents (because you yourself chose the 5th via the power item)
Basically, forget the power items. JUST use the Destiny Knot and the Evertsone (which passes down the nature of the parent 100% of the time) and just keep track of what babies are getting what stats. So if a baby has 2 IVs, swap that with one of the parents that only has 1. When they're both 2 IV parents, keep breeding till you get 3 then swap one out for that one. Keep going like this till you gradually get parents with 4 or 5 IVs and then you will eventually get one with the spread you want. (this is why the Everstone is important, as you will always get the correct nature so that leaves at least one thing that isn't random chance) just be patient.
Now as for checking their IVs, EVERYONE keeps suggesting the IV judge, but then the person is always left to come back to the message board to find out what his phrases mean, and even then the phrases only mean a RANGE of IVs, not the exact number (unless you get 31) so what I always suggest (and I think I'm the only one in the Pokemon breeder universe that does so) is simply do a ton of wonder trades to rack up Pokemiles, go onto the PGL website and cash them in for 100 Rare Candies (they're half the price of rare candies in game using pokemiles) then hatch 5 eggs at a time, save, level each one up to level 20 and then plug their stats and nature into an IV calculator like this:
https://www.serebii.net/games/iv-calcxy.shtml and you will know what stats COULD be 31. Whichever one has the most stat that COULD be level 31, take note of. Reset, level it up again to a high enough level that the calculator gives you the EXACT IVs of that pokemon, and then you know! It sounds like it takes a long time, but it really doesn't. It took longer to type that out than to actually do it.
Now, the good thing about the calulator is that, except for a few pokemon, at level 20 everything that COULD be 31 will be listed as 30 or 31, and since you KNOW you have parents with 31IV in stats and you are using the destiny knot, it's a safe bet that those stats ARE 31 IVs, so simply reset, swap that pokemon with one of the daycare parents and keep doing that until you have the offspring you want. I have gotten 5IV offspring within a couple of hours this way. (keep in mind, however, that there have also been times it has taken me days and in one case two WEEKS to get the spread I want, so it's not necessarily a fast process, just keep that in mind)
And FYI: Reseting is for you to get your Rare Candies back and to put your pokemon back down to level 1. That's why you need to make sure you save BEFORE you level up your pokemon.