I need info about baby doves please help?

A cat attacked a nest and this little dove is the only one who survived. I know I probably shouldn't have rescued it but I couldn't watch it die. I have had him for one night and have him on a heating pad. I have been feeding him kitten formula every three to four hours. I hole the formula to his beak and he drinks it himself. Some people say to not give this formula to him but others say its ok. I don't have the money to buy baby bird food formula so I wanted everyones input. And I wanted to know when they start eating solids. He looks to be about 10 to 15 days old. P.s our local rehad center will not answer the phone and my last three birds died because I couldn't get ahold of them