looking for birth family of twins, adopted in Nebraska 1934

Identical twins, born December 1933 to Frances M. (Jump) Cochran (birthmother). Father is unknown. Birth names were Arthur Francis and Charles Frederick Cochran on one set of papers. Another set lists their last name as "Miller". They were adopted by William and Valborg Jensen. Names changed at adoption to Alton Frederick and Allen Francis. Frances M. Cochran is apparently deceased, but she had many other children, who we would like to locate. The father of her many other children was Clarence Lester Cochran, however Clarence Lester Cochran died in 1929, before the twins were conceived. I have searched for many, many years for the siblings of the twins, but they seem to have fallen off the face of the earth! By looking at the court and adoption records, it appears that she may have been forced to give up the twins, so it is possible that she was forced to give up her older children as well. The court proceedings took place in Thurston County, Nebraska. The twins were born in Sioux City, Iowa. They were placed in the custody of the orphanage know as "White Hall", in Lincoln, Nebraska - several months before they were adopted. I located a distant cousin of Frances, who was able to provide me with her ancestry as well as some photos of her, but no one knows what became of her children, nor who fathered the twins. Any help, big or small, is appreciated. (I am the eldest granddaughter of Alton Frederick Jensen, born Charles Frederick.)