do you think you could make a out of lettuce and maggots and feed them nothing but that it would cut costs way down for chickens just being raised for meat
maggot and lettuce diet
I am guessing you were talking about iceberg lettuce since it is the cheapest type of lettuce. There is practically no nutrition in iceberg lettuce. Do a google search of it if you don't believe me. It does contain a few vitamins. The percentage of one of those vitamins is 7% and the others are lots lower. To be healthy, birds need more than a trace of a few vitamins and some protein to be healthy.
I think it would work (high fat, high protein, low carb, what's not to like?) but one type of maggots may not be enough. For example mealworms are low in methionine, and have, IIRC, no vitamin B12. If it has to be one type, BSF is probably best, although I do not know their B12 content. Even better if you raise red worms in BSF castings, you extend your meat by 50% or so.
Also, heading lettuce as noted by others is not great. Leaf lettuce is better, but there are anyway many options to grow a lot of leaves with higher nutritional content. I have a type of cutting chicory that pumps leaves all season, and all animals prefer it to lettuce. But you could also consider clover, brassica, grass, and mixtures of the above, cool season and warm season growers should both be included. some types of perennial clover can cope with continuous grazing.