What to do about this underdeveloped plant

this plant is very underdeveloped compared to my other 3 i have 2 blz and 2 kandy kush under a 400 watt mh there is plenty of ventilation and my ppm is 230 and ph levels are 6.3, what do you sappose i should do about the underdeveloped plant and the yellow leaflets on this plant?

all these view and no comments ? are you kidding me

If it is just one bad in the bunch, maybe just a weak one. Every plant is gonna be a little different

It also looks like it's stretching for light

yeah thats what i figured i mean it grows lol but the leaves dont get bigger and grow non symetrical like way more leaf on the left than the right side of the leaflets, thast only on that one plant tho. and iv moved them to 6 inches under my MH. it is very well ventilated and i think that will solve the stretching prob. im going to keep growing it and see what happends. and since they are raised so close to my mh i had to take them out of my drip sysytem so im going to handwater for another week hopefully that will cure the yellow and stetching. i mean worse comes to worse i can just flower 3 plants but i would like to flower 4 tho! lol

I got some great white shark from GHS that had a couple weak ones in the grow, but i did nurse them thru and got bud.

yea thats good to know, a little more bud is better than no more bud lol.

temps too low?
400w mh is alot for a seedling... it might just be using all that light to develop a root system.