Check with the humane society. In the past I've known them to come out and spay and neauter ferrals for free and then leaving them back where they found them.
You should look into TCAP in Hurst (I think). They have a feral cat program for just that scenario
You can go to the Humane Society where you can call them or you can call the Fort Worth Animal Shelter and I do believe that they will do it for free and might be a small charge no more maybe than 10 to 20 bucks
The kitten we adopted was not spayed but part of the adoption fee covers that. I don't believe they do surgery on site.
You need a rescue like Mid Cities community cats to help. If you can catch them yourself, tcap can help for very very very low cost. Otherwise, a TNR group can help you catch them for spaying and vaccines
Procedure to spay feral cat
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