Oooops, second time is a charm.....

Here is a link that might be useful: Tomato Pics

Tough to see detail.

Also would help to know what you're doing, or not. For instance: water -- what method, how often and how long?

I'm watering with soaker hoses, in four hour intervals, once a week. I've added detailed pics of plants.

Here is a link that might be useful: Tomato Details

look like they're not getting enough water.

Where is the soaker hose in relation to the stem? i.e. how far away?

Also, what kind of soil is it? sandy or clay

Soaker hose is ran 6-8" from stem. The soil is excellent black, river bottom amended with decomposed chicken manure, pine shavings, & diatomaceous earth (I raise chickens). Ph is 7.1. I propagate my vegetables & annuals in my own greenhouse.I mulch & spray my tomatoes weekly with a cocktail of Sevin, Daconil, Calcium once they've been planted. These tomato plants started showing sign of yellowing bottom leaves very early & has slowly progressed to each plant.