Mortality rate 40 per cent

From my cloneing room to my veg room I an suffering a harsh mortality rate. I started with 10 and i am to six healthy. Here are some pics start to now. Any one interisted in helping what do you wont to know? there are two that just died and two struggling, One ( the last pic ) the leafs are small compared to sisters It did get hot Is This heat stress.???

If it was heat stress i would imagine the plants would have recovered from it. How much heat and how long for are we talking?

100 for 2 weeks

During this summer i experienced similar conditions, my plants looked rough but they pulled through, although they were stunted. Have you had problems like this before?

This is the first one that looked like that. First full summer too