Don't thin it.
Warm it up, ideally using a double boiler (saucepan of water) to hand warm.
Don't overheat it, as this destroys the protein antibodies.
When hand warm, it should pass through a bottle or stomach tube as required, sometimes very thick colostrum needs the plunger on a syringe for a stomach tube, or a wider hole in a teat.
The best colostrum is good thick custard!