But the congregation of St Hilda’s Church, Ellerburn, near Thornton-le-Dale, is determined to continue holding services, said churchwarden Liz Cowley.
The Grade II*-listed Saxon church was closed for several months last year after droppings and urine from the protected creatures made it impossible to hold services.
Hundreds of whiskered, pipistrelle and natterer bats – all protected by law from being disturbed – have made the church their roost.
“We are working closely with Natural England and they paid for the church to be cleaned because we had three weddings and a Christening booked,” said Mrs Cowley.
Hopes of encouraging the bats to move into a specially-built loft at a nearby farm’s barn, and another in the church lychgate, have failed, she said.
The congregation have spent thousands of pounds on heated bat lofts in a failed attempt to lure the creatures from the church.
“At the last count there were about 250 bats in the church,” said Mrs Cowley.
While some of the bats had surveyed the special lofts, they decided not to move in permanently and returned to their homes in the church.
Natural England provided a cleaning team for the special services to go ahead, and the 12-strong congregation carries out a DIY cleaning before Sunday services.
“We use plastic sheeting to hold the droppings and when we remove it the smell goes as well,” said Mrs Cowley. “The smell can be horrendous”.
A licence was granted by Natural England to block up the main entrance to the church to deter the bats, but despite that, the breeding colonies, which include the natterers bat, have re-established themselves.
The conservation agency says it recognises the situation has been “extremely frustrating” for the congregation and says it will help resolve the issue.
The next big service, said Mrs Cowley, will be the Christmas carol event which attracts a congregation of over 100, packing the tiny historic church.
“We are determined it will be looking spick and span for that,” she added.