For the first week of their life my chicks are on newspaper....no crooked toes......ever. The original story about newspaper is that it caused spraddled legs which makes a lot more sense than crooked toes, but neither happens and I have been doing it this way for 50 years. Over the years I have had crooked toes, but not because of the brooder substrate. Folks use a lot of excuses to explain away crooked toes and they make believable story's but..........
Walt
I use paper towels for the first week or so and then pine shavings. One crooked tow this year. None last year.