One of the contractors housing some of the surge of illegal immigrant children from this summer offers them a petting zoo with miniature ponies, a tilapia fish farm operation and guitar lessons, according to documents releasedThursday by a senator who questioned whether the plush accommodations were a good use of taxpayers’ money.

Sen. Charles E. Grassley, Iowa Republican, said it seemed excessive to pay the $329 that Southwest Key Programs, the contractor, charged per child per day at one of its California facilities in Lemon Grove, California. Another facility in El Cajon cost taxpayers $316 per child per day.

Mr. Grassley said it was particularly questionable to pay those high rates even as the White House came to Congress asking for more money to handle the surge of children earlier this year.

“It is disturbing that HHS is funding such expensive facilities despite claiming to be unable to meet basic needs for UACs,” Mr. Grassley said in a letter to Health and Human Services Secretary Sylvia Mathews Burwell, using the acronym for Unaccompanied Alien Children, which is the term the government has given to the illegal immigrant youths who jump the border without their parents.

An HHS spokesman didn’t return a message seeking comment on Thursday.

A spokeswoman for Southwest Key said they were just seeing the letter and would try to respond on Friday.

The Washington Times has previously reported on some of the conditions for facilities housing the children elsewhere, including culturally sensitive music piped in to their rooms, meals tailored for lactose-intolerant stomachs and guaranteed phone privileges to be able to call their family either back home in Central America or in the U.S., where many of the children’s parents are already living illegally.

In the documents Mr. Grassley revealed Thursday, Southwest Key says it has a fish farm where they cultivate more than 1,000 tilapia. It also says it has an organic orchard with lemon, orange and grapefruit trees and an organic garden that provides vegetables for their kitchen.

The children are paid $1 a day in allowance, according to the documents.

HHS has kept many of the details of the children’s care from the public, with officials saying they believed Congress had instructed them to protect the children’s privacy, which includes the locations and conditions of their housing.

The Times made an open-records request for details of an HHS contract with Southwest Key in early July, and has yet to receive a response. The law gives agencies a month to respond.