Seed Starting Mat as Heat Source?

[Snido]

My family has a large garden and we start everything from seed. We are gettting into chickens this year, and I am trying to dual use as much of the existing equipment as I have. We bought 15 layers that will arrive in March, average temperature in my area then should be around 65F during the day and 45F at night. I have 2 of these mats https://www.amazon.com/gp/product/B00P7U259C/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1 that we use to warm soil up to 85/90F so that we can germinate peppers reliably. I am going to use a stock tank as a brooder, and was wondering if or how I could use these? If I use a metal tank can I put them under the tank and heat the floor? If I go with one of my plastic tanks can I just pop it in the bottom and tape over the cord? I have seen setups where people have put heat pads over a little trellis to make a heat cave, is that the safest way to go? My 2 concerns are ensuring I am providing enough heat while also protecting them from their own curiosity with and possibly pecking the cord. Thanks for the help!

 

[U_Stormcrow]

Plenty of people use seed starting mats in brooder boxes with success. Reptile mats, too. I considered it myself, but they were too small for my needs, I went with a heat plate instead.
and for reasons of easier clean up, I but a big old towel on the floor - helps with leg problems (I frequently hatch ducks) particularly on slick plastic tote floors, and makes cleaning the box daily SO SO SO much easier.

 

[Ridgerunner]

Personally I'd go with it as a cave, the method is proven even in cold weather. I would not be comfortable with it under the tank, not sure it would keep them warm enough. I'll include a link to a thread about the cave method. It's long and you have to dig through it to get some of the details but it is a good method.

Mama Heating Pad in the Brooder (Picture Heavy) - UPDATE | BackYard Chickens - Learn How to Raise Chickens

Another option would be to use it to provide heat to a hover. Think of a shallow box elevated a bit with the open side down. Warm air rises so the hover traps that air. If you do an internet search try "Ohio brooder" as your search term.

 

[Kiki]

A clippy lamp with a regular light bulb, not a heat lamp bulb, works great.

 

[cityeggs]

I had the same idea of repurposing a seedling mat rather than buying something new. I tried the mat by itself and it didn't get warm enough, so I bought a separate thermostat (and an independent thermometer bc I didn't want to just rely on the one on the thermostat). It seemed to be ok when set up inside our house in late summer for 2 chicks; however, the mat I had did not keep the temp very steady (if you search seedling mat, the thread should come up where I asked about it and reported back). Even with the thermostat set with a narrow range, the on/off cycle meant that there was at least a 20 degree swing between high & low temp. I didn't worry too much because mine were indoors and it was relatively warm still, so the surrounding air temp did not get below 70 even at night and I watch their behavior and they seemed content, though at first they spent most of their time in the cave. I'm sure different pads and different thermostats vary in their quality and effectiveness, but I did not trust mine for use under colder conditions, and I doubt a seedling mat itself without a thermostat will work; typically, they're only capable of increasing the temp 10-15 F above the ambient air temp. I have chicks now indoors, and I went with the heating pad this time and the temp seems much more consistent (now that I have the heat setting right, and also switched from a baking rack to a piece of curved hardware cloth with taped edges).

I agree with Ridgerunner about the benefits of setting up a cave rather than underneath like a reptile mat; the cave method means that there is a zone where the heat is trapped, which will keep them warmer than if it is just underfoot and the heat is very quickly lost to the air around them.

I also strongly recommend testing your set-up now to see if you can get consistent temperatures with your mat so that you have time to change if necessary, including set up outside to see if there's adequate heat under those conditions. You can get a relatively cheap indoor/outdoor thermometer that records the high/low temp within a 24 cycle so you don't have to constantly check. Ideally, you'll want to check the temp of the air inside the cave as well as the surface temp reading. There's a lot of discussion of what those temps should be - I don't have enough experience to give definitive numbers, but surface temp shouldn't go too high that it could burn them, and air temp below shouldn't get too low. There's a fair amount of disagreement about what the air temp in the cave should be, since it's not the same heat transfer as with a bulb - the cave primarily relies on direct contact heat transfer to the chick's back vs. convection with a bulb. At the very least, you'd want to have a sense of the range you have - how warm you can get it under those conditions so that if chick behavior shows they're too cold (huddling, crying) you know that you can increase the heat to make them comfortable.