test2 <- test %>%  mutate(grouped_id = row_number()) %>%
                    group_by(BroodID) %>%
                    summarise_each(funs(na.omit))

structure(list(ID = c(2010.3, 2010.3, 2010.3, 2010.3, 2010.33,
 2010.34, 2010.38, 2010.38, 2010.39, 2010.39, 2010.4, 2010.4,
 2010.4, 2010.4, 2010.4, 2010.41, 2010.41, 2010.42, 2010.42, 2010.44,
 2010.44, 2010.46, 2010.46), F = structure(c(5L, 5L, 12L, 12L,
 11L, 8L, NA, 3L, NA, 1L, NA, 2L, 2L, 6L, 6L, NA, 7L, NA, 9L,
 NA, 4L, NA, 10L), .Label = c("T206434", "T206553", "T931169",
 "T931286", "T961275", "V470937", "X250041", "X250109", "X250195",
 "X250568", "X251067", "X251069"), class = "factor"), M = structure(c(2L,
 2L, 11L, 11L, 6L, NA, 9L, NA, 10L, NA, 1L, 1L, 4L, 4L, NA, 8L,
 NA, 3L, NA, 7L, NA, 5L, NA), .Label = c("T206824", "T206994",
"T960191", "T961486", "X250567", "X250779", "X250851", "X251046",
 "X251066", "X251074", "X251116"), class = "factor")), row.names = c(NA,
 23L), class = "data.frame")