The ICAR-DMR raw material table gives typical dry weight values: wheat straw about 0.6 per cent nitrogen, deep litter chicken manure 3.0 per cent, wheat bran 2.0 per cent, soybean meal 6.5 per cent and cotton seed meal 7.0 per cent.
These are typical values, not your values. A worked example in the same chapter uses chicken manure at 2.6 per cent and straw at 0.40 per cent. Manure from a young flock on fresh litter is not manure scraped off a shed floor after a year. Start from the table, then test your own lot when a laboratory is reachable.