Are oats and lard suitable for chicks

Hello everyone! Hope someone can help...I've looked on different sites but can't find a clear answer.

During winter we started feeding the birds oats mixed with melted lard which especially the blackbirds and robins enjoyed. 

I have continued to put this out, alongside dry food and soaked mealworms and raisins (have tried soaked dog biscuits but they aren't interested!). Most blackbirds and robins eat the oats but fly off with a beakful of mealworms for their young. But a few of the blackbirds and one robin ignore the mealworm and fly off with a beakful of 'lardy oats'! I'm wondering if this will be harmful for the young and whether to stop putting it out, or if they do know what they're doing and it's an ok food. (I am aware of lard not being suitable in hot weather...keep it in the fridge and just but a bit out at once)

Don't want to do more harm than good!